SB 

'■^25 



U. S. DEPARTMENT OF AGRICULTURE. 

BUREAU OF PLANT INDUSTRY- BULLETIN NO. 143. 



B. 1. >iA\AA)\\AY. ariefnf liuredu. 



PRINCIPLES AND PRAriTTCAL METHODS 
OF CURING TOBACCO. 



W. W. CURNER. 

PlIYSIOLOrJIST, ToBAf'f'O TXVES TKJ ATIONS. 



ISSriH Fl.UKKARY 1(5, IStdV). 




WASHINGTON: 

O O ^ K I ; N M K XT P K 1 N T I N ( J OFFICE, 

I i» 9 . 




Glass 3 3^7 
Book 'GZS~ 



^ 



U. S. DEPARTMENT OF AGRICULTURE. 

BUREAU OF PLANT INDUSTRY— BULLETIN NO. 143. 

B. T. GALLOWAY, C'/ttf/o/ J? (M-COM. 



PRINCIPLES AND PRACTICAL 
OF CURING TOBACCO. 



W. W. GARNER, 
Physiologist, Tobacco Investigations. 



<-■' t. 



Issued Fkukuary 16, 1909. 




WASHINGTON: 

government printing office. 



10 9. 



u^- 



V 



.<v^ 



BUREAU OF PLANT INDUSTRY. 

PhysiologMand Pathologist, and Chief of Bureau, Beverly T. Galloway. 

Physiologist arid Pathologist, and Assistant Chief of Bureau, Albert F. Woods. 

Laboratory of Plant Pathology, Erwin F. Smith, Pathologist in Charge. 

Fruit Disease Investigations, Merton B. Waite, Pathologist in Charge. 

Laboratory of Forest Pathology, Haven Metcalf, Pathologist in Charge. 

Cotton and Truck Diseases and Plant Disease Survey, William A. Orton, Pathologist in Charge. 

Pathological Collections and Inspection Work, Flora W. Patterson. Mypologist in Charge. 

Plant Life History Investigations, Walter T. Swingle, Physiologist in Charge. 

Cotton Breeding Investigations, ATchihald D. Shamel and Daniel N. Shoemaker, Physiologists in Charge. 

Tobacco Investigations, Arcliilmid D. Shamel, Wightman W. Garner, and Ernest II. Mathewson, in 

Charge. 
Corn Investigations, Charles P. Hartley, Physiologist in Charge. 
Alkali and Drought Resistant Plant Breeding Investigations, Tlaomas II. Kearney, Physiologist in 

Charge. 
Soil liac.teriology and Water Purification Investigations, Karl F. Kellerman, Physiologist in Charge. 
Bionomic Investigations of Tropical and Subtropical Plants, Orator F. Cook, Bionomist in Charge. 
Drug ami Poisonous Plant and Tea Culture Investigations, Rodney II. True, Physiologist in Charge. 
Physical Laboratory, Lyman J. Briggs, Physicist in Charge. 
Agricultural Technology, Nathan \. Cobl), Crop Technologist in Charge. 
Taxonomic and Range Investigations, Frederick V. Coville, Botanist in Charge. 
Farm Management, William J. Spillman, .Vgriculturist in Charge. 
Grain Investigations, Mark .Vlfred Carleton, Cerealist in Charge. 
Arlington Experimental Farm and Horticultural Investigations, Lee C. Corbett, Horticulturist in 

Charge. 
Vegetable Testing Gardens, William W. Tracy, sr., Superinten<lent. 
Sugar-Beet Investigations, Charles O. Townsend, Pathologist in Charge. 
Western Agricultural Extension, Carl S. Scofleld, .Vgriculturist in Charge. 
Dry-Land Agriculture Investigations, E. Channing Chilcott, .Vgriculturist in Charge. 
Pomological Collections, Gustavus B. Brackett, I'omologist in Charge. 

Field Investigations in Pomology, William .V. Taylor and G. Harold Powell, Pomologists in Charge. 
Experimental Gardens and Grounds, Edward M. Byrnes, Superintendent. 
Foreign Seed and Plant Introduction, David Fairchild, Agricultural E.xplorer in Charge. 
Forage Crop Investigations, Charles V. Piper, Agrostologist in Charge. 
Seed Laboratory, Edgar Brown, Botanist in Charge. 
Grain Standardization, John D. Shanahan, Crop Technologist in Charge. 
Subtropical Garden, Miami, Fla., P.J. Wester, in Charge. 

Plant Introduction Garden, Chico, Cal., W. W. Tracy, jr.. Assistant Botanist in Charge. 
South Texas Garden, Brownsville, Tex., Edward C. Green, I'omologist in Charge. 
Farmers' Cooperative Demonstration Work, Seaman A. Knapp, Special Agent in Charge. 
Seed Distribution (directed by Chief of Bureau), Lisle Morrison, Assistant in General Charge. 



Editor, J. E. Rockwell. 
Chief Clerk, James E. Jones. 



Tobacco In\i;stigations. 
scientific staff. 



A. D. Shamol, Physiologist: W. W. Garner, Physiologist; and E. H. Mathewson, Crop Technologist, 

jointly in charge. 

W. M. Hinson, W. W. Green, and G. W. Ham's, 'Criip Technolotiists. 

J. B. Stewart and Otto Olson, Tobacco Experts.' . -" * 

J. B. Norton, Physiologist. 

H. Wooslcy, R. P. Cocke, J. E. Blohm, H. K. Hayes, and D. E. Brown, Special Agents. 

C. L. Foubert, Chemist A id. 

B. G. .\nderson, CoHaborator. 



irrrER of transmittal. 



U. S. Department of Agriculture, 

Bureau of Plant Industry, 

Office op the Chief, 

Washington, D. C, Octoher 28, 1908. 

Sir: I have the honor to transmit herewith a manuscript entitled 
" Principles and Practical Methods of Curing Tobacco,'- and recom- 
mend that it be published as a bulletin of the series of this Bureau. 

The proper management of the curing barn requires some knowl- 
edge of the physiological changes which are taking place in the curing 
process. There is a rapidly increasing demand for such information. 
For this reason the bulletin has been divided into two parts, one dis- 
cussing the principles of curing and the second the practical methods 
of curing based on the principles discussed in the first part. 
Kespect fully, 

B. T. Galloway, 

Chief of Bureau. 
Hon. James Wilson, 

Secret a nj of Aq/'iculture. 

3 
143 



CONTENTS 



Part I. — Principles op Curing Tomacco. Page. 

IntroiUiction ' 

Changes in the composition and properties of the leaf wliieli take i)lac'e 

in the curing process <*^ 

The ripening of tobacco 9 

Curing the picked leaves compared with curing on the stalk 10 

The air-curing process 12 

First stage of air-curing 13 

Second stage of air-curing 14 

The most favorable conditions for air-curing 15 

Pole-sweat, or house-burn 17 

Air-curing as affected by heat and ventilation IS 

Available methods of applying artificial heat 20 

Modifications of the air-curing process 21 

The Hue-curing process 22 

Changes in the composition and properties of the leaf 22 

Conditions affecting the rate of cure 23 

Management of Hue-curing 24 

Curing tobacco with open tires , . - 25 

Part II. — Practical Methods ok Curing as Applied to the Various 
Types op Tobacco. 

Cigar tobaccos 27 

Construction of the barn for curing cigar tobacco 27 

Harvesting cigar tol)acco 30 

Curing cigar tobacco 33 

Stripping and assorting cigar tobacco 35 

Shade-grown cigar-wrapper leaf 36 

Management of the curing barn 38 

Burley tobacco 39 

Harvesting Burley tobacco 40 

Curing Burley tobacco , 40 

Assorting and packing Burley tobacco 40 

Sun-cured tobaccf > 41 

Yellow tobacco 41 

Construction of the barn for curing yellow tobacco 41 

Harvesting yellow tobacco , ■ 44 

Curing yellow tol)acco 45 

Handling yellow tobacco after curing 46 

Heavy export tobaccos 47 

Harvesting export tobacco 48 

Curing export tobacco 48 

Handling export tobacco 49 

Perique tobacco 50 

Index 53 

143 • 5 



ILLUSTRATIONS. 



Fig. I. Type of barn used in northern cigar-tobacco districts, showing tlie 

arrangement of horizontal ventilators 29 

2. Type of barn used in southern cigar-tobacco districts, showing the 

arrangement of ventilators . 30 

3. Tobarc(i field, showing the method employed in spearing ])lants on a 

lath, with the hurdle used for supporting the latter during the opera- 
tion 32 

4. The best form of wagon rack for hauling plants to the curing barn 32 

5. A very convenient wagon rack for hauling baskets of picked leaves to 

the curing barn 37 

6. The interior of a cigar-tobacc-o barn, showin* the arrangement of tier 

poles and the method of hanging picked leaves 38 

7. Type of tobacco barn used in the Burley district of Kentucky 39 

8. A typical log barn used in curing yellow tobacco, showing the venti- 

lator in the gable and the outside portions of the heating system 42 

9. Sketch showing the arrangement of furnaces and flues in a barn 

adapted for curing yellow tobacco 43 

10. Stick with wires used in the yellow-tobacco districts for hanging 

picked leaves in the curing barn 45 

143 



B. P. I.— 430. 



PRINCIPLES AND PRACTICAL METHODS OF 
CURING TOBACCO. 



PART I.-PRINCIPLES OF CURING TOBACCO. 



INTRODUCTION. 

The tobacco plant is very sensitive to the sniTonndings under 
which it is forced to grow. Its physical characters, as well as its com- 
position, are greatly influenced by soil, climate, fertilizers, and the 
treatment which it receives at the hands of the growers. The quality 
of the finished product, moreover, depends to a large extent on the 
care and skill which are displayed in the curing and fermentation 
processes. Again, tobacco is subject to the attacks of numerous 
insect enemies and to fungous diseases in the seed bed, in the field, 
in the curing shed, in the packing house, and even after it leaves the 
hands of the manufacturer. Hence, it will readily be seen that the 
greatest care and skill must be used by the grower, as well as by the 
packer and manufacturer, in order to turn out a first-class finished 
product. There are, in fact, few, if any, other important croi)s the 
values of which are so dependent on the painstaking care, skill, and 
good judgment of the producer. And of the various factors enter- 
ing into the successful production of a superior quality of tobacco, 
none is more important than the proper management of the curing 
process, for a crop of the highest promise may be irretrievably dam- 
aged in the curing barn under unfavorable conditions. 

The tobacco industry has become highly specialized in this country 
and has been made the subject of a great d?al of study and experi- 
mentation on the part of growers; but although the practical side 
of the industry has attained its highest development in this, its 
native, countr3% it has not received anything like the attention the 
subject merits at the hands of our scientific investigators. This is 
particularly true of the curing process, for while the process in- 
volves many complex changes in* the composition and properties of 
the leaf which greatly affect its commercial value these changes are 
for the most part imperfectly understood. As a natural result, 
64764— Bui. 143—09 2 "^ 7 



8 . PRINCIPLES AND METHODS OF CUEING TOBACCO. 

progress in the development of satisfactory practical methods has 
been slow, and this phase of the industry is, as a whole, still in a 
comparatively crude state. 

Some of the more important principles of successful curing are 
well established, however, and it is to the interest of every grower 
to acquaint himself as far as practicable with the nature of these 
fundamental facts. Of course, long experience is essential in this 
as in other features of tobacco growing, but it is also undoubtedly 
true that the experienced operator will be the better able to meet 
the various unexpected contingencies which are sure to arise from 
time to time by carefulh^ studying the underlying principles gov- 
erning the cure. The more thoroughly the grower undei-stands the 
nature of the changes going on in the leaf during the curing and the 
most faxorable conditions for bringing about these changes, the 
easier will it be for him to adopt proper methods for securing these 
essential conditions. The first portion of this l)ulletin, therefore, is 
devoted to a discussion of those changes wliich take place in the 
curing prcx-ess and the most favorable conditions for accomplishing 
those results. In this discussion the subject-matter has been freed 
from unnecessary technicalities, so that it is hoped it may be read 
with interest and profit by the practical grower. It is further hoped 
that the suggestions made concerning many important phases of the 
subject which have not as yet been worked out may serve to direct 
the attention of intelligent and progressive growers to the need of 
studying further some of these problems. Following this discussion 
of the subject of curing from the theoretical standpoint will be found 
a rather complete, though concise, description of the methods now 
actually in use for curing the various types of leaf produced in the 
dilfei-ent tobacco sections. 

CHANGES IN THE COMPOSITION AND PROPEBTIES OF THE LEAF 
WHICH TAKE PLACE IN THE CURING PROCESS. 

If a sample of tobacco taken from the field at the usual time of 
harvesting were dried out rai)idly in an ()\en and manufactured into 
appropriate forms for smoking or chewing, it would scarcely be 
recognized as tobacco by the consumer. Above all else, the grower 
should keep in mind the fact that curing is not simply the drying 
out of the leaf but involves a number of other important changes in 
composition, which can only be lirought about under certain definite 
conditions. There are several ditierent classes of tobacco, each 
adapted to certain trade requirements, and the details of the curing 
are variously modified to suit the class to which the finished product 
is to be assigned. T>\ modifying the conditions of curing, some of 
the important properties of the leaf are forced to develop along 

143 



THE RIPENING OF TOBACCO. 9 

quite different lines. Maii}^ of the most valuable (qualities of one 
type may not be at all desirable in another type, so that it is im- 
portant that the grower first acc^uaint himself with the trade require- 
ments of the particular type which he can produce to the best ad- 
Aantage, and then ascertain as nearly as possible the most favorable 
conditions of curing for developing the fine qualities of that type. 

THE RIPENING OF TOBACCO. 

Soon after the leaves of the tobacco plant reach maturity they 
undergo marked changes in color and other properties and these 
changes constitute the ripening process. The young growing leaf 
has an intense green color, showing that it is quite rich in the nitrog- 
enous constituents which go to make up the living or vital part of 
the leaf and which are active in building up the food supply of the 
plant. At about the time the leaves of the plant as a whole have 
reached their maximum power of elaborating the food supph^ the 
flower head begins to develop. This food supply, consisting of starch 
and other similar substances, is carried from the leaf into the seed 
head to furnish the necessary food for the development of the seed. 
This accomplished, the leaves have completed their full task and they 
now pass into a period of gradual decay. In practice, however, 
the plant is topped, so that the seeds are not allowed to develop. 
Making a last effort to reproduce itself, the plant now sends out 
secondary shoots or suckers, but these, too, are removed by the grower. 
Under these circumstances, the food built up by the leaves^ is not 
carried away to other parts of the plant but accumulates in the leaves 
themselves. The result is that both the size and body of the leaf are 
increased. 

The principal indication that the above-mentioned processes are 
taking place is a decided change of color. When the reserve food 
supply of the mature leaf is no longer required for the nourishment 
of other parts of the plant it is deposited in the leaf tissue in the 
form of starch granules, Avhile the green coloring matters are dis- 
solved and carried to the younger, growing parts. This interchange 
causes the appearance of the light-tinted flecks so characteristic of the 
ripe leaf. Moreover, the accumulation of the starch gi-anules in the 
leaf causes it to become brittle, so that it snaps when folded between 
the fingers, another characteristic sign of ripeness. Xow the replace- 
ment of the complex nitrogenous constituents, including the green 
coloring matter, by the starchy matter has a most important effect 
on the color, flavor, elasticity, and finish of the leaf. Indeed, much 
of the success in curing tobacco depends on harvesting it just 
at the right time, when it is neither too ripe nor too green. Thus, in 
the case of cigar tobacco, the brightest, clearest, brown colors are 

14.H 



10 PRINCIPLES AND METHODS OF CURING TOBACCO. 

obtained when the leaves are harvested just before they woidd be 
called fully ripe. If harvested before this period the colors will be 
dull or " muddy " and too dark, because they still contain too much 
of the green coloring matters with which the brown coloring sub- 
stances are closely associated. On the other hand, if the leaves are 
allowed to become too ripe, the colors will be uneven and mottled 
and lacking in freshness because of a deficiency of the green coloring 
matters. For the same reasons a green leaf after curing will be tough 
and leathery, while an overripe one will be " strawy " and lifeless to 
the touch. Finally, since the materials which develop the flavor and 
aroma are derived from the green nitrogenous comjiounds. the fully 
ripe leaf will be deficient in these qualities, while the green leaf will 
possess them much more highly developed. 

It is evident, then, that the lower, fully mature leaves of the plant 
when moderately ripe will be best suited for the production of cigar 
M'rappers bright in color and having the necessary elasticity but 
neutral in flavor, while the upper leaves harvested before they have 
fully matured Avill give the best fillers, having the required flavor 
and aroma but being much darker in color than the wrappers. In 
curing the bright yellow tobacco it is necessary that the leaf be fully 
ripe, for the content of the green coloring matter must be reduced to 
the mininnmi consistent with the required toughness in order to ob- 
tain the cured leaf free from green or lirown discoloration. 

CURING THE PICKED LEAVES COMPARED WITH CURING ON THE 

STALK. 

The details of the curing process are variously modified to suit the 
requirements for the different classes of tobacco, but whatever this 
subsequent treatment nuiy be there are two general methods of har- 
vesting the crop and arranging it in the barn. In the one case the 
leaves are picked from the stalk as they ripen and are arranged on 
strings or sticks suitable for hanging in the curing shed. In the 
other method the leaves are not removed from the stalks, but the 
latter are cut off near the ground and suspended in an inverted 
manner in the barn. Of course all the leaves on the plant do not 
ripen at the same time, so that the tobacco is harvested at such time 
as will give the greatest number of the best leaves at the proper stage 
of ripeness. This necessitates a considerable sacrifice in both bottom 
and top leaves, since the former are overripe and the latter still im- 
mature, but the method saves labor. 

There has been much discussion from a practical as Avell as from 
a scientific standpoint as to the relative merits of the two methods, 
and each has its advantages and its disadvantages. Both give 
satisfactory results when properly carried out, and the question as 

143 



CURING PICKED LEAVES AND CURING ON STALK. 11 

to which is -the better in any given case mnst be decided hirgely by 
the local conditions, such as the amount and kind of the labor supply, 
the barn space available, and the like. In the end the problem 
resolves itself into the question of the relative value of the crop to 
be cured, and nearly all of the highest priced tobaccos are now 
being cured by the method of picking the leaves, generally spoken of 
as " priming." This is more expensive than the method of curing on 
the stalk, but possesses the great advantage that it is possible to har- 
vest all the leaves just at the right stage of maturity, and this fact 
becomes important when the tobacco is produced under a highly 
intensive system invohdng a large outlay of capital. 

Although, as has been said, both methods are capable of giving 
good results, there are undoubtedly differences in the character of 
the cured product as obtained in the two processes. To understand 
the differences brought about by these two methods of curing, we 
must remember that the leaves and the stalks remain alive for sev- 
eral days or even weeks after harvesting, depending on the condi- 
tions which prevail in the curing barn. They are enabled to remain 
alive so long as they retain sufficient moisture by means of the reserve 
food supply which has been stored up. The outer edges of the leaf 
are first Ivilled by loss of moisture, and the unused portion of the food 
supply is withdrawn toward the midrib, which is the last part of the 
leaf to die. When the leaves are picked from the stalk, of course this 
transfer of the food materials can get no farther than the midrib of 
the leaf, but when the leaf remains attached to the stalk these food 
materials pass into the stalk to keep this alive and to supply nourish- 
ment to the young suckers which are struggling to develop. 

Every one who has cured cigar tobacco on the stalk must have been 
impressed by the remarkable vitality of the stalk itself as well as of 
the young suckers, whereby they remain alive for many weeks before 
the point of starvation is reached. On account of the water con- 
tained in the stalk, which gradually passes into the leaf to replace 
that lost by evaporation, the leat under these conditions remains alive 
for a much longer period than when separated from the stalk. Since 
a portion of the reserve food supply of the leaf is transported into the 
stalk when the leaf is left attached to the stalk, and since, further, 
the leaf remains alive for a longer period under these circumstances, 
and so itself uses up more of its accumulated food, we should not be 
surprised that leaves cured under these conditions are considerably 
lighter in weight than those cured after being separated from the 
stalk. The most careful experiments on this point have shown that 
picked leaves are about 11 per cent heavier after curing than those 
cured on the stalk. It has also been found that when suckers are 
left on the stalk at the time of harvesting there is a still greater loss 

143 



12 PRINCIPLES AND METHODS OF OUBINO TOBACCO. 

in weight by curing the entire phmt. We have very little accurate 
information as to the relative effects of the two methods of curing on 
the quality of the leaf, but, other things being equal, it is probable 
that the picked leaves will have more of the so-called " gum " and 
more body than those cured on the stalk. 

In the case of the yellow tobacco, the curing on the stalk is modi- 
fied in that the stalk is split open for almost its entire length. This 
class of tobacco, furthermore, is all cured by artificial heat, and both 
of these circumstances, of course, operate to greatly shorten the life 
of the stalk after it is placed in the barn. Hence there is little op- 
portunity for the transportation of material from the leaf into the 
stalk. But here again curing on the stalk serves to keep the leaves 
living for a longer period than is the case when they are picked. 
This class of tobacco is very rich in starchy matters, and while these 
may not be transported into the stalk they would be more completely 
consumed by the leaves themselves when cured on the stalk. This 
naturally gives a tougher leaf, possessing relatively more gummy or 
resinous matter. At aiw rate, it is commonly believed by growers in 
the older yellow-tobacco districts that the best plug wrappers can 
only be obtained b}^ curing the leaf on the stalk. Xevertheless, a 
good grade of wrapper is obtained in the newer districts of the yel- 
low-tobacco belt l)y ])icking the leaves for curing. 

THE AIR-CURING PROCESS. 

Apart from the two different methods of harvesting and hanging 
the tobacco in the barn, the method of conducting the curing process 
is variously modified according to the uses for which the leaf is 
intended. These differences in procedure pertain chiefly to the rate 
of drying out of the leaf, and this in turn is controlled mainly by 
the use of artificial heat. The character of the cured product is 
greatly modified by these different methods of procedure, and it is 
necessary to consider separately the types cured Avith and those 
cured without the aid of artificial heat. In the latter case the process 
is known as air-curing and a large proportion of our finest tobaccos 
is cured by this method. 

Practically all of the cigar tobaccos wherever produced and the 
immense quantities of Burley tobacco grown in Kentucky and 
adjoining States are cured without the use of artificial heat except 
during a siege of very wet weather. The tobacco is placed in the 
barn in the green state, usually after having been wilted, and the 
subsequent curing is controlled simply by opening or closing the 
ventilators as occasion demands. In considering the changes taking 
place in the leaf during the curing process, this may be divided into 

143 



FIRST STAGE OF ATR-CURTNG. 13 

two periods, diirino- tlie first of which the leaf remains alive, while 
in the second the changes which occur have no connection with its 
life activities. 

FIRST STAGE OF AIR-CURING. 

The changes which occur during the first period of the curing, and 
wliich are by far the most important, are dependent upon the life 
activities of the minute cells which make up the body of the leaf. If 
a ripe tobacco leaf is killed outright with chloroform or with heat 
and then ]5laced under normal curing coiulitions, it does not develop 
the characteristic properties of a well-cured leaf. It is certain, 
therefore, that in order to secure a satisfactory cure the conditions 
must be such that the leaf will remain alive long enough to allow 
these necessaiT changes to take ])lace. In the curing shed the leaf 
undergoes a slow process of starvation unless it is killed prematurely 
by injury, such as bruising, by heat, or by too rapid drying out. Of 
course, the leaf must have food in order to remain alive, and this 
comes from the reserve supply which has been stored up. 

We have seen that the ripe leaf is very rich in starch and that one 
of the important changes in the curing is the disappearance of this 
starch, which is consumed by the living portion of the leaf itself. 
Now. if the leaf is killed by bruising, rapid drying, or heating too 
high there is no means of removing this starch, and the tobacco is 
harsh, lifeless, and " strawy." The vitality of the tobacco plant is 
remarkable, and parts of the leaf will continue to live for several 
weeks in the curing barn under favorable conditions. After the 
starch is all used up it is probable that some of the nitrogenous con- 
stituents are attacked as a last means of prolonging the life of the 
residual living matter. 

Along with these changes in composition the green color is replaced 
by a lemon-yellow. This change from green to yellow takes place 
in all tobacco, whatever the method of curing may be, if it is prop- 
erly conducted. The green coloring matter of the tobacco leaf, 
called chlorophyll, is found in all green plants in very similar, but 
not identical, forms. During the period in which the leaf tissue is 
undergoing starvation, this green coloring matter is more or less 
completely changed into colorless substances, and the appearance of 
the 3'ellow color marks the approaching death of the leaf. If the 
green leaf is killed outright soon after harvesting by bruising oi" 
rapid drying out, the green color can not be removed by any sub- 
sequent treatment the leaf may receive; but if the leaf remains a]i-\e 
for two or three days, even though the green color has not fully 
disappeared, that which remains may be removed by sweating or 
fermentation. 

143 



14 PEINCIPLES AND METHODS OP CURING TOBACCO, 

It must not be thought that the yellow coloring matter is formed 
during the curing process directly from the green coloring material. 
This yellow coloring matter is contained in the green leaf before it is 
harvested and also after it has turned brown. The yellow is simply 
obscured in these cases by the more intense green or brown. In fact, 
the yellow becomes apparent in the ov^erripe plants in the field, and 
when the brown coloring matters are deficient it may still be visible 
after the leaf has been fermented. It is interesting to note that the 
green color is never entirely destroyed in the inner parts of the leaf, 
even after fermentation followed by a long period of aging. 

SECOjS'D STA(iE OF AIR-CURING. 

The full development of the yellow color marks the end of the first 
period of the curing. In the second period the changes which take 
place are not dependent on life processes, and hence can be accom- 
plished in the fermentation bulk as well as in the curing barn. The 
fermentation is, in fact, merely a continuation of the second stage of 
the curing. The changes taking place in this case are for the most, 
part quite different from those occurring in the first stage of the curt. 
After the leaf is dead, no more of the starch is consumed, nor are the 
protein nitrogenous compounds attacked. The changes consist mainly 
in the further breaking up of the products formed in the first stage 
of the ciu-ing. One of the most important changes is the development 
of the brown color. Here again it nnist be understood that the brown 
coloring matters are not derived from the yellow, jior are tliey derived 
directly from the green coloring material. They are formed by a 
process of oxidation Avhich does not take place till the cells of the leaf 
are dead. As soon, therefore, as portions oi the leaf die they at once 
begin to turn brown, provided sufficient moisture is present. The two 
essentials for the development of the brown color are a sujiply of 
oxygen, which is obtained from the air. and a sufficient amount of 
moisture. This development of the brown color, which is begun in the 
second stage of curing, is always completed in the fermentation of the 
tobacco, and the chief danger as regards the curing is that the develop- 
ment will proceed too far because of excessive moisture, causing the 
leaf to cure to6 dark. The amount of coloring matters in the leaf 
probably depends chiefly on the conditions as to soil, fertilizers, and 
climate under which the plant is grown, and so is not under the con- 
trol of the operator in the curing. But the depth of the brown color 
is governed by the extent to which the oxidation is allowed to proceed, 
and this factor can be controlled by regulating the moisture supply. 

It has been explained how the imjiortant changes in the first stage 
of the cure can only be effected b}- keeping the leaf alive for a suffi- 
cient period of tin.p and that once the leaf has been killed these 

143 



MOST FAVORABLE CONDITIONS FOR AIR-CURING. 15 

changes can not be accomplished by any subsequent treatment. On 
the other hand, those changes occurring in the second stage of the 
curing take jjhice after the leaf is dead and are largely continued in 
the subsequent fermentation. The extent of these changes is gov- 
erned by the external conditions of temperature, moisture, light, and 
air sujoply. It is quite impossible to control these conditions properly 
in the curing shed, Avhereas they can be readily managed in the sweat 
room. It is therefore desirable to complete the second stage of the 
cure as rapidly as practicable and then to keep the tobacco compara- 
tively dry until it is ready for fermentation. A great deal of air- 
cured tobacco, especially of the cigar types, is seriously injured in 
quality every year because of the damp or cold weather encountered 
during the last stage of the curing and in the interim before the 
tobacco is removed from the barn. These unfavorable weather condi- 
tions greatly prolong the final drying out of the leaf and cause a sort 
of cold sweat to take place, which prevents a normal sweat in the pack- 
house. It is a common experience among packers to find that tobacco 
cured under these conditions will not heat up properly in the bulk. 

As regards quantity, the most important change in the curing is the 
loss of water. The tobacco leaf normally loses about 75 per cent of its 
green weight in the curing, and by far the greater portion of this loss 
is water. Thus it has been found that 8,000 plants grown on an acre 
of ground in the Connecticut Valley and yielding about 1,800 pounds 
of cured leaf weigh when harvested something like 8 tons, of which 
fully C) tons are water. To cure tobacco successful!}^ this vast amount 
of water must be removed under such conditions and at such rate as 
will best allow the other important changes to take place. 

THE MOST FAVORABLE CONDITIONS FOR AIR-CURING. 

The question now arises as to the most favorable conditions for air- 
curing and the means of controlling these conditions. It has been 
shown that the principal changes taking place in the first stage of 
curing are due directly to the activities of the living cells while they 
are passing through a period of gradual starvation; hence, the condi- 
tions should be such as are most favorable to these activities. These 
cells are killed b}^ bruising, so that it is important to avoid injury in 
this way in the harvesting as far as possible. Again, these cells are 
killed by excessively low or high temperatures and by the rapid loss 
of water. The life activities of the tobacco plant practically cease at 
temperatures below 40° F., while they increase as the temperature 
rises, until at about 125° F. the living cells are rapidly killed. These 
activities are also greatly lessened by loss of water and cease as soon 
as the leaf becomes dry. In practice, the most favorable temperatures 
for curing lie between the limits of G0° arid 100° F., and the relative 
64764— Bui. 143—09 3 



16 PRINCIPLES AND METHODS OF CURING TOBACCO. 

luiniidity should be about 85 per cent. Under these conditions the 
leaf will graduall}^ lose its water, but Avill never be out of case or 
order and the curing will proceed smoothly. If the humidity becomes 
much higher, pole-sweat will develop on the leaves most advanced in 
the curing, while if the humidity falls much below this figure the leaf 
will dry out too rapidly. 

In the second stage of the curing, when the leaf begins to turn 
brown, there is no longer any need for keeping the air in the barn so 
moist, and the relative humidity may be lowered to about 80 per cent, 
and later still further reduced to G5 or TO per cent, until the stems are 
dry. It is desirable to prevent the tobacco from coming into high 
case after curing until it is to be taken down, and it should be stripped 
and packed as soon as possible after the curing is completed. So long 
as artificial heat is not used the temperature will never become too 
high for favorable curing, but it frequently becomes so low as to 
seriously interfere with the process. 

Unfortunately the growers at the present time have very limited 
means of controlling the temperature and relative humidity in the 
barn in the air-curing process. It is indeed a remarkable fact that 
the methods employed in this process are the crudest of all those used 
in curing tobacco, for the operator is almost at the mercy of the 
weather conditions. If the season is too dry, the tobacco ''hays 
jown" — that is, simply dries out like hay — while if it is too wet, the 
tobacco is seriously damaged by pole-sweat. Of course marked ad- 
vances have been made in this method of curing in recent years, but 
these improvements consist chiefly in the construction of better barns, 
whicli is only one ste[) in the right direction. It remains for some 
one to work out a practical method of controlling the temperature and 
humidity in the barn when the weather conditions are unfavorable. 
Many thousands of dollars' damage to the tobacco crop results annu- 
ally from lack of means for nuiintaining the proper conditions in the 
barn during the curing period, and this loss can never be overcome 
until satisfactory means are provided for conducting the cure inde- 
pendently of outside weather conditions. 

All experienced tobacco growers are aware of the serious damage 
likely to result from pole-sweat during the periods of very wet 
weather, but few of them appear to fully appreciate the extent of the 
injury in quality caused by the opposite extreme of excessively dry 
weather. This fact is probably due to the circumstance that injury 
by pole-sweat is of such a character that it is promptly recognized, 
since the tissues of the leaf are actually disintegrated, while, on the 
other hand, tobacco which has been dried out too rapidly is per- 
fectly sound, and its inferior quality is not fully apparent until after 
it has been fermented, when it is likely to be attributed to other 

143 



POLE-SWEAT, OR HOUSE-BURN. 17' 

causes. Although in this case the vahie of tlie leaf is never entirely 
destroyed, the damage is more widespread and of more frequent 
occurrence, so that in the aggregate it probably amounts to more 
than that caused by pole-sweat. The average grower, in his anxiety 
to avoid 2)ole-sweat, is apt to hasten the first stage of the cure far 
too rapidly to secure the best results. 

POLE-SWEAT, OR HOUSE-BURN. 

This disease, which is especially to be dreaded during periods of 
prolonged wet weather accompanied by relatively high temperatures, 
occurs the world over where tobacco is cured without the use of heat. 
It is caused by some of the lower organisms which attack those con- 
stituents of the leaf which give it toughness and stiffness. As a re- 
sult, the tissues soften and lose their coherency, so that the leaf sim- 
ply falls apart. These organisms are not true parasites — that is, 
they do not attack living matter — so that pole-sweat can not occur 
until after the leaf tissue dies. But of course some parts of the leaf 
may die much sooner than others, so that pole-sweat may appear 
before the entire leaf is dead. Xaturally, it first attacks those leaves 
which have been bruised or broken in harvesting. Again, it appears 
first on the lower leaves of the plant, which die more rapidly than 
the upper, greener leaves. Its development is greatly favored by 
crowding the plants or the leaves too closely, thus preventing the 
necessary ventilation. 

The organisms which cause this trouble are not active at very low 
temperatures, so that pole-burn does not appear to any extent in 
cold weather. Furthermore, they only thrive in the presence of an 
abundance of moisture. The three essential conditions for the rapid 
spread of the disease, then, are: (1) Tobacco which lias passed 
through the first stage of the cure or which has been killed by bruis- 
ing or other injury; (2) a temperature ranging from GO'^ to 100° 
F. ; and (3) a relative humidity of 00 per cent or more, which checks 
the evaporation from the leaves, causing them to become soggy. ITnder 
these conditions it is amazing to note the rapidity with which the 
trouble spreads throughout the barn. Of course, conditions favor- 
able to pole-sweat may exist for short periods without the appear- 
ance of the disease, but it will certainly develop if these conditions 
continue from twenty-four to forty-eight hours. 

True pole-sweat implies more or less decay of leaf tissue, but the 
leaf may be discolored without materially affecting its soundness. 
This is caused by short periods of excessive humidity which do not 
continue long enough for the development of the organisms which 
attack the leaf structure. In this case dark-colored oily drops collect 

143 



18 PRINCIPLES AND METHODS OF CURING TOBACCO. 

on the surface of the leaf, especially at the tips, and when these 
evaporate dark spots are left. Such spotted leaves are almost worth- 
less for bright wrappers, although the tissue is perfectly sound. 

There is no doubt that the remedy for this disease lies in controlling 
the humidity in the curing l)arn during periods of excessively damp 
weather, but so far no cheap practical method of accomplishing this 
has been devised. It is believed by some growers that ventilation 
affords protection, but if the relative humidity outside of the barn is 
above DO per cent, ventilation alone can not possibly do any good. The 
whole problem lies in keeping down the humidity, and the only prac- 
tical method of doing this consists in the combined use of heat and 
ventilation. Various means of introducing heat into the barns dur- 
ing unfavorable weather conditions have been tried, and some of these 
hav(^ been successful under certain conditions. We have seen that 
either excessive dryness or excessive moisture in the barn during the 
curing process will seriously injure the value of the tobacco. Where 
the color of the product is of importance, injury will result from ex- 
cessive humidity whether or not pole-sweat appears. The control of 
(his disease is therefore merely one phase of the more general prob- 
lem of maintaining in the barn the most favorable conditions for 
the develo[)nient of the finest (jualities in the leaf. 

ATR-CURIXG AS AFFECTED BY HEAT A>«M) VENTILATION. 

One of the pressing needs at the present time in the production of 
air-cured tobacco is some adequate means of controlling the tempera- 
ture and humidity in the curing barn whereby the process can be con- 
ducted more or less independently of the outside weather conditions. 
With the hope of stimulating interest in this problem among growers, 
some of the fundamental principles which must be made use of in 
any i)ractical solution are briefly stated in the following paragraphs. 

Tol)acc() as it is hung in the barn contains an enormous amount of 
water which must be removed by evaporation from the surface of 
the leaves and at such rate as will allow certain important changes 
in composition to take place. So long as the minute cells of the leaf 
remain alive they resist the loss of water, so that it is only given up 
slowly unless the surrounding air is quite dry. On the other hand, 
as soon as the cells are dead, marking the end of the first stage in the 
curing, the remaining water is set free and will ooze out to the surface 
of the leaf whether or not the surrounding air be dry. 

Accordingly, the first stage of the cure can be prolonged as far as 
is necessary bv keeping the surrounding air moist, while in the sec- 
ond stage the water must be removed as fast as it comes to the sur- 
face of the leaf by keeping the air sufficiently dry if we are to avoid 
injury from pole-sweat or discoloration. At the time the tobacco is 

IL". 



EFFECT OF HEAT AND VENTILATION ON AIR-CURING. 19 

hung in the barn, water is evaporating from the surface of the leaves, 
and this evaporation continues until the surrounding air is saturated 
"with moisture. A given volume of air, or, more correctly, the space 
containing this air, is capable of taking up a certain amount of 
moisture and no more at any particular temperature. Hence, the 
evaporation from the fresh tobacco leaves will soon cease unless the 
surrounding air which has become saturated is replaced by a fresh 
supply of drier air. In other words, we must have ventilation. 

Contrary to the general impression, moist air is lighter than dry 
air at the same temperature, and consequently the saturated air in 
the barn will tend to rise to the top, while the heavier, drier air will 
flow in from the outside to replace it. Again, warm air is lighter 
than cold air and will rise, so that when the sun shines on the roof 
of the barn, thus warming up the upper sections of the inclosed air, 
this warmed air is forced upward by the cooler, heavier air near the 
ground. For these reasons the natural course of ventilation in the 
curing barn is for the cooler, drier air to enter the barn near the 
bottom, pass upward through the tobacco, thus absorbing more mois- 
ture and becoming warmer, thereby growing constantly lighter, and 
finally to pass out of the top of the barn. Of course, if the wind be 
blowing briskly the air may be driven directly through the barn when 
ventilators are opened on the sides, thus providing a sort of forced 
A^entiitttion. 

In moderately dry weather it will be seen that ventilation is all 
that is needed to secure favorable curing conditions, provided the 
temperature is not too low, but that ventilators should be provided at 
the top of the barn as w^ell as on the sides. In very drj' weather the 
evaporation from the leaves should be kept in check by having the 
barn built as tight as possible and by keeping all ventilators closed 
during the day. In this case it is well to open up the ventilators 
during the night in order to insure plenty of fresh air in the barn. 
Unfortunately this precaution against injury from dry weather can 
not be satisfactorily observed under present conditions, owing to the 
danger of pole-burn which would be incurred in case a prolonged 
season of wet weather should follow. Yet there is no doubt that 
many growers allow their tobacco to dry out too rapidly by opening 
all ventilators on dry days. 

Wliile the rate of curing can be satisfactorily controlled when the 
weather conditions are just right or when it is too dry by proper 
management of the ventilation, it is quite different in either cold or 
very wet weather. If the temperature is low, the curing changes are 
stopped, although the tobacco may continue to dry out. In this 
case the leaf is simply dried and not cured. During rainy or foggy 
weather the air is practically saturated with moisture, and since it 

143 



20 PRINCIPLES AND METHODS OF CURING TOBACCO, 

can not take up any more it is obvious that ventilation alone is use- 
less under these circumstances. Xow, the capacity of the air for 
water vapor is greatly influenced by the temperature ; thus, at 52° F. 
a cubic foot of saturated air contains 0.000G3 pound of water vapor, 
while at 72° F. the capacity is increased to 0.00122 pound. By rais- 
ing the temperature of the air 20 degrees we double its capacity f(n- 
holding moisture. It is obvious, therefore, that if air which is sat- 
urated with moisture enters the barn and if its temperature is raised 
20 degrees the relative humidity drops from 100 per cent to 50 per 
cent, or the air becomes about as dry as on an average bright, sun- 
shiny day. Given some suitable means of maintaining the tempera- 
ture in the barn from 15 to 20 degrees higher than that of the outside 
air, combined with proper ventilation, the problem of controlling the 
curing conditions would be solved. 

If the air becomes saturated at any given temperature, any lowering 
of this temperature will cause some of the moisture to be deposited 
in the form of liquid. This is wlw pole-sweat j^rogresses so rapidly 
Avhen moderate temperatures are followed suddenly by warm, wet 
weather, for the warm, saturated air from the outside coming in con- 
tact with the cooler tobacco is chilled and actually deposits moisture 
on the leaf. For the same reason an insufficient quantity of heat is 
worse than none, for the temporarily warmed air absorbs more 
moisture from the tobacco in the loAver part of the barn, but is cooled 
before it reaches the top and deposits this moisture on the tobacco in 
the upper part of the barn. Consequently, enough heat must be 
supplied to Avarm the barn up to the top and thus drive out the moist 
air. 

AVAILABLE :METII0DS OF APPLYIXO AKTIFK'IAL HEAT. 

One of the fir^t essentials is that the heat be produced at the bottom 
of the barn and properly distributed so that in rising it will be forced 
to pass through all portions of the tobacco. Otherwise local cur- 
rents will be set up, while a large portion of the air remains stagnant. 
Herein lies the great objection to the open fires which are sometimes 
resorted to. It is impossible to avoid overheating the tobacco hang- 
ing directly over the fires, while that between the fires does not re- 
ceive enough heat. Obviously the greater the number of fires the more 
satisfactory will the result be. This method of applying heat has 
been successfully used in sections where the leaves are picked from 
the stalk before curing, but when the leaves are cured on the stalk it 
has not been found satisfactory. In addition to the uneven disti'ibu- 
tion of the heat and the difficulty of maintaining anything like a 
miiform temperature a considerable amount of space in the barn must 
be sacrificed, for in hanging the tobacco at least a part of the lower 
tier must be left vacant. At best it is only a means of warding off 

143 



MODIFICATIONS OF THE AIR-CURING PROCESS. 21 

pole-sweat and does not reach the broader problem of maintaining 
the proper curing conditions in the barn at all times. 

Steam as a source of heat presents many obvious advantages. This 
is apparently the only means of heating whereby the temperature 
can be distributed uniformly and readily controlled. Of course the 
first cost of installing a steam-heating system would be considerable, 
but it would last indefinitely. With a system of this kind the curing 
could be carried out independently of the weather conditions. In 
considering the cost and value of any system of heating it should be 
remembered that protection against pole-sweat is by no means the 
only object to be sought. It rarely happens that the most favorable 
conditions of temperature and humidity prevail during the curing- 
season, and there can be no doubt that the value of the crop would be 
materially increased by the judicious use of a steam-heating system. 
The practical question is whether the increase in the quality of the 
leaf would be sufficient to warrant the use of this system. 

Recent experiments with a system of flues for supph'ing heat simi- 
lar to those employed in curing yellow tobacco have given promising 
results. Here, again, the principal difficulty to be overcome lies in 
the i^roper distribution of the heat. The barns used in the flue-curing 
districts are not more than 24 feet square, so that the flues are never 
more than G or 8 feet apart. It will be seen that a large number of 
flues, with a corresponding number of furnaces, would be required 
for the barns in the air-curing districts. It would scarcely be prac- 
ticable to set these flues up in permanent form, so that it would be 
necessary to take them down before putting in the tobacco and before 
taking it down again after curing. It is not a difficult matter, how- 
ever, to set up the flues, and they may prove to be the practicable mean 
between the ideal but costly steam-heating system on the one hand and 
the unsatisfactory method of using open fires on the other. 

MODIFICATIONS OF THE AIR-CUIIING PROCESS. 

The air-curing has been discussed mainly from the standpoint of 
cigar tobaccos, but the same principles apply to other t^-pes, more 
particularh^ the Burley tobaccos. The changes which take place in 
the first stage of the cure are of the same character, but the final color 
changes are somewhat different. Instead of the characteristic brown 
of the cigar leaf the Burley should have a golden red color after 
curing. In each case, however, the brightest colored leaf commands 
the highest price, so that Burley tobacco, like the cigar leaf, should 
not be exposed to excessive moisture in the last stages of the cure. 

In a few counties of Virginia a type of plug tobacco is produced 
which is known as " sun-cured tobacco." The tobacco is hung on scaf- 
folds, exposed to the sun for several days, and then transferred to the 

143 



22 PRINCIPLES AND METHODS OF CURING TOBACCO. 

barn. Avhere the curing is comi^leted without the use of artificial heat. 
This method of curing has not been investigated, and practically 
nothing is luioAvn of the diiferences in composition between sun-cured 
and ordinary- air-cured tobaccos. 

THE FLUE-CURING PROCESS. 

The distinctive feature of the flue method of curing is that the 
barn is provided with a system of large i)ipes through which the 
heated air is j^assed throughout the curing period. The smoke does 
not come into contact with the tobacco and the cure is completed 
within a few days. One of the jjrincipal factors controlling the value 
of the leaf cured by this method is the color, and the two prime con- 
ditions for success in this respect are the right kind of soil and the 
proper control of the curing. The color most desired is a character- 
istic bright lemon-yellow, and. in addition, the leaf should have suf- 
ficient gummy matter to give it flexibility, but it must also be of a 
spongy character, so that it will absorl) large quantities of the sauces 
used in manufacturing chewing tobacco. 

CHANGES IX TlIK ( ( )M1>< )SIT1( IX AND PltOI'EUTIKS OF THE LEAF.. 

In the flue-curing method, just as in the air-curing process, the prin- 
cipal changes in composition brought about in the curing are de- 
pendent on the life activities of the minute cells in the leaf, and the 
nature of the changes in the two methods is the same. The main dif- 
ference lies in the extent or completeness of these changes. The 
typical bright yellow tobacco at the time of harvesting is riper than 
most tobaccos cured without the use of heat. Partly on this account, 
and also because of the character of the soil on which it is grown, 
this type of leaf is relatively richer in starchy matter and poorer in 
organic nitrogenous materials, particularly the coloring matters. 

Because of the difference in composition, combined with the effects 
of higher temperatures and more rapid drying, the green color is re- 
moved much more rapidly. It is to be remembered that here, as in all 
other types of tobacco, the yellow color is not formed directly from 
the green, but is already present in the green leaf. The rapid appear- 
ance of the yellow color does not afford sufficient time for the trans- 
formation of all the starchy matter, and as soon as this stage is 
reached the drying must be hastened so as to prevent any further 
change in color. EAndently. then, the flue-curing method consists 
essentially in the hastening and shortening of the first stage in the 
air-curing process, Avhile the second stage of the cure, made apparent 
by the development of the brown color in the case of cigar tobaccos, 
is not allowed to take place at all. 

143 



CONDITIONS AFFECTING THE RATE OF CURE. 23 

CONDITIONS AFFECTING THE RATE OF CURE. 

It is interesting to note the large number of formulas or rules 
which are in use in curing this type of tobacco, any of which will 
give satisfactory results in certain cases. This is due partly to differ- 
ences in the tobacco when harvested and partly to the fact that all 
of these formulas are based simply on the temperature in the barn, 
with scarcely any reference to the humidity, which is really the con- 
trolling factor in the rate of curing. The principal function of the 
artificial heat is to regulate the humidity, and obviously this is also 
dependent on the amount of water in the tobacco and on the prevail- 
ing weather conditions. 

The capacity of the air for holding moisture, and consequently its 
drying capacity, depends principally on its temperature, and air which 
is already saturated has no drying power until its temperature is 
raised. Satisfactory curing can only be accomplished by proper regu- 
lation of the rate of drying, and this depends chiefly on the humidity 
of the air in the bam. From these facts it is clear that in order to 
maintain a definite rate of drying by controlling the humidity, the 
temperature in the barn must bear a certain relation to that of the 
outside air, and the difference in temperature inside and outside the 
barn will be influenced by the humidity of the outside air. In warm 
weather the temperature inside the barn must be higher than in cool 
weather, and in rainy or in foggy seasons it must be higher than in 
clear, dry weather. 

In addition to temperature there is another equally important fac- 
tor in controlling the humidity in the barn, and consequently the 
rate of drying, and this is ventilation. If the barn were perfectly 
tight, the air within would of course soon become saturated, and 
the inevitable result would he that the tobacco would sweat; that is, 
drops of water would collect on the surface of the leaves. The 
warm saturated air in the barn must therefore be constantly replaced 
by the cooler, less humid outside air, and hence proper means of 
ventilation should be provided. It is astonishing to note the small 
number of growers who fully appreciate the importance of ventila- 
tion. Most barns are built without any provision for ventilation, 
and the only reason that curing can be STiccessfully done in these 
cases is that the barns are not sufficiently tight to prevent the natural 
ventilation caused by the higher temperatures within. Frequently 
this natural ventilation is insufficient, and at the critical moment the 
tobacco is irreparably damaged by discoloration because of lack of 
means of ventilating the barn to remove the excessive moisture. On 
the other hand, there are times when it is desirable to check the 
rate of drying, so that it is important to provide ventilators at the 
top and bottom of the barn which can readily be closed Avhen occa- 
sion demands. 

647G4— Bill. 143—09 1 



24 PRINCIPLES AND METHODS OF CURING TOBACCO. 

MANAGEMENT OF FLUE-CURING. 

The completion of the curing proper is marked by the develop- 
ment of the yellow color. This transformation from a green to a 
yellow color, along with other attendant changes, takes place while 
the leaf is still living, and if the leaf is quickly killed by heat or by 
being rapidly dried it will be impossible to remove the green color. 
At temperatures above 125° F. the leaf is rapidly killed, so that this 
limit must not be exceeded during the yellowing process. The great- 
est danger in this first stage of the curing, however, is that the leaf 
will dry out so rapidly as to prematurely kill it. After the leaf is 
dry no amount of heat can remove the green color. The yellowing 
process may be accomplished at any temperature ranging between 
80° and 120° F.. provided the humidity in the barn be properly 
managed. 

Care nnist be taken to avoid drying the leaf too rapidly during the 
first stage of the cure, but as it begins to yellow the humidity in the 
barn must be materially decreased by slowly raising the tempera- 
ture and gradually increasing the ventilation. If these two points 
are carefully observed there will be little trouble from so-called 
" sponging '' or " scalding."' As soon as the leaf has become yellow 
the whole problem is to regulate the drying so as to prevent any 
further change in color. This second stage of the curing, known as 
" fixing the color," is the critical period and requ.ires the closest atten- 
tion. There are two fundamental facts of the greatest importance 
in this connection, namely, that the brown or red color can not 
appear until the leaf is killed and that it develops oidy in the presence 
of cousiderable moisture. 

The appearance of the yellow color indicates that the leaf has 
reached the dying stage, but it still contains a large amount of water, 
When the leaf tissue dies all the moisture within the leaf is released 
and will rapidly move to the surface, so that unless this moisture is 
promptly removed the leaf will certainly begin to turn a reddish 
brown color. To avoid this injury to the tobacco the heat must be 
raised very slowly, so as to kill the leaf tissue gradually, and, more 
important still, plenty of ventilation must be provided to take away 
the moisture. The temperature should not be allowed to fall during 
this period. 

In addition to this reddening of the leaf, commonly called " spong- 
ing," which is caused by failure to remove the moisture by sufficient 
ventilation, there is often trouble from a somewhat different dis- 
coloration, known as "scalding," or '-splotching." The primary 
cause of this is advancing the temperature too rapidly while the leaf 
still contains much moisture. The rapid increase in temperature 

143 



CUEING TOBACCO WITH OPEN FIRES. 25 

kills the leaf cells so rapidly that the water which is set free brings to 
the surface of the leaf some of the coloring matters from within, and 
the result is a bluish black discoloration. 

CURING TOBACCO WITH OPEN FIRES. 

In the districts where heavy shipping tobacco is grown the so- 
called " fire-curing " is almost universally employed. This method 
is really a sort of combination of the air-curing and flue-curing proc- 
esses, differing from the former in that artificial heat is invariably 
applied in the later stages and from the latter in that the. heat is 
applied by means of small open fires. The first stage of the cure is 
identical with the ordinary air-curing, and the changes which take 
j)lace are of the same character. After the tobacco has been curing 
for four or five days, either on scatfolds in the field or in the barn, 
small fires are started and only very moderate temperatures main- 
tained for about twenty-four hours. After this the temperature may 
be considerably increased. Wlien the leaf and half the stem are 
cured the fires are withdrawn and the tobacco allowed to soften up 
again, after which the fires are again started. 

The tobacco in the fire-curing districts is characterized by an 
extremely thick, heavy leaf, very lich in nitrogenous matters, and 
hence it cures very slowly. Before the fires are started the greater 
portion of the starch has been used up, and this change is necessary 
to give the leaf the required flexibility. The low heat which is then 
applied is necessary to hasten the curing, particularly the removal of 
the green color, and to reduce the moisture in the leaf so as to pre- 
vent blistering or splotching when the temperature is advanced. The 
application of heat to this tobacco as soon as harvested would not 
afford sufficient time for the curing changes to develop before the 
leaf became dry. On the other hand, if the removal of the green 
color were not hastened by the use of artificial heat the time required 
for this change would be so long as to cause the appearance of the 
reddish brown color. 

Tobacco cured by this process is exposed directly to the smoke 
from the open fires, and consequently acquires a characteristic flavor 
and odor. The substances of a creosotic nature absorbed from the 
smoke have marked antiseptic properties and prevent the leaf from 
suffering injury in shipment to foreign countries. 

143 



PART II.-PRACTICAL METHODS OF CURING AS 
APPLIED TO THE VARIOUS TYPES OF TOBACCO. 



CIGAR TOBACCOS. 

To a certain extent every tobacco plant produces the three com- 
ponents of the cigar, the upper leaves being used for the filler, while 
the lower ones furnish the binder and wrapper. In practice, however, 
the soil and climatic conditions of the different cigar-tobacco districts 
do not produce these three grades of leaf to the same degree of excel- 
lence, so that these districts are generally classified according to the 
particular grade of leaf they produce to the best advantage. Thus, 
the light, sandy soils of the Connecticut Valley produce a thin, fine- 
textured leaf especially adapted for w^rappers but lacking in the flavor 
and aroma essential for filler purposes, whereas the heavy soils of 
Ohio produce a heavy leaf poorly suited for w^rappers but prized as 
a filler because of its characteristic flavor and aroma. 

The bulk of the cigar-tobacco crop at the present time is grown in 
the States of Massachusetts, Connecticut, New York, Pennsylvania, 
Wisconsin, Ohio, Florida, Georgia, and Texas. The finest grades of 
wrapjDer leaf are grown in a few counties of western Florida, south- 
ern Georgia, eastern Texas, and in the Connecticut Valley, while 
Wisconsin is known as a binder State and Xew York, Pennsylvania, 
and Ohio produce mainly filler grades. All cigar tobaccos are cured 
without the use of artificial heat, and the general methods of pro- 
cedure are essentially the same in all the cigar-tobacco-growing States 
except in the case of the shade-grown types of Florida and Con- 
necticut. The methods of harvesting and curing this type of leaf 
differ sufficiently from those commonly in use to warrant special con- 
sideration. 

CONSTRUCTION OF THE BARN FOR CURING CICiAR TOBACCO. 

Great advances have been made in recent years in the construc- 
tion of barns for curing cigar tobacco, and many of those now in 
use are well adapted to this purpose. The main improvements have 
been in building the barns more nearly weatherproof and in provid- 
ing more efficient means of ventilation. In some sections there has 
been a marked tendency to mcrease the size of the barns, so that 
143 27 



28 PBINCIPLES AND METHODS OF CUEING TOBACCO. 

now it is not nnnsnal to find them 300 feet or more in length. The 
chief consideration in this increase of size has been one of economy 
in constrnction. but it is undoubtedly true that the best barn is 
the cheapest in the end, so that the deciding question should be 
whether the larger barn is better adapted to controlling the curing 
conditions. So long as the grower is dependent on outside weather 
conditions in curing his tobacco the danger from pole-sweat will be 
greater in the larger barn, because of the increased difficulty in main- 
taining the necessary ventilation, so that any gain in economy of 
construction is likely to be more than oH'set l)y this danger. 

In building a good barn the two principal considerations to be kept 
in mind are to construct it as nearly air-tight as possible and at the 
same time to provide an efficient system of ventilation, for in the ab- 
sence of any method of supplying artificial heat these constitute the 
only means of controlling curing conditions. A site should be chosen 
for the barn which is thoroughly drained and sufficiently removed 
from other buildings to allow free access of air. It should be as near 
the tobacco field as possible, for convenience in harvesting. A con- 
\'enient width for the barn is 32 feet, while the length should be some 
nndtiple of 1(> feet if the tier poles, which are 10 feet long, are to 
run lengthwise of the building. ]\Iany barns are built 4 tiers high, 
but the curing can be better controlled when the building is only 3 
tiers high to the i)late. The tobacco should not hang within 3 feet 
of the ground, so that the first tier of poles should be at least 8 feet 
from the ground and the remaining tiers 5 feet apart. Thus, a barn 
3 tiers high will be 18 feet to the plate, or one 4 tiers high will be 23 
feet to the plate. The sills for the frame should be raised at least a 
foot al)Ove the ground, resting on brick or stone piers. The roof is 
given a steep pitch and generally carries two additional tiers for 
hanging tol)acco, the lower being comjDOsed of 4 rows and the upper 
of 2 rows. 

The posts, plates, and beams used for the frame should not be less 
than T by 7 inches. At intervals of IG feet posts, frames, and girders 
are set up across the barn the same as at the ends, thus dividing the 
frame into l()-foot sections, known as " bents." The importance of 
building the frame of stout, substantial timbers can be appreciated 
when it is remembered that each bent of the dimensions stated above 
is capable of holding 4,500 plants, which in the green state will weigh 
at least 20,000 pounds. The girders on the ends and on the bents for 
carrying the lower tier of poles should be made removable, while those 
for the two upper tiers should be well braced. The tier poles on which 
the tobacco is hung are IG feet long and may be sawed out, though 
round poles serve just as well. They must be stout enough to carry 
800 pounds. 

143 



CONSTRUCTION OF BARN FOR CURING CIGAR TOBACCO. 29 

The boards for the sides and ends shouhl be of first -chiss quality, 
lined, and of uniform width. All cracks should be battened with thin 
strij)s about 3 inches wide, so as to make the structure as nearly 
weatherproof as possible. At least every third board should be hung 
on hinges as a ventilator. The boards may be put on either vertically 
or horizontally, and there are numerous Avays of arranging the venti- 
lators. If the boards are put on horizontally those used for venti- 
lators are hinged from the upper edge and are generally tied together 
by vertical strips, so that all of them may be operated from the 
ground. When the siding is put on vertically those boards used for 
ventilators may be hinged either from the top or side, and in the 
former case are also usually tied together. In any case the ventilators 




**•««« 



Fig. 1. — Type of bam used in northerr cigar-tobacco districts, sliowing tlie arrangement 

of liorizontal ventilators. 

on the sides should extend nearly up to the eaves and tho.se on the 
ends should be extended to the roof. There are some desirable fea- 
tures in all of these methods of ventilating, but the vertical system of 
A-entilators hinged at the top is more in accord with scientific princi- 
ples and possesses a number of advantages over the others. These 
ventilators furnish l)etter protection from the direct sunlight and 
from the wind, while they always afford the largest opening for ad- 
mission of air near the bottom, which is desirable since natural circu- 
lation is always upward. Extending along the entire length of the 
sides, a horizontal ventilator should be provided at the bottom for 
admitting air below the sills. Comparatively few barns at ' the 

143 



30 PRINCIPLES AND METHODS OF CUEING TOBACCO. 

present time have any provision for ventilation on the roof, but any 
method of controlling pole-sweat in wet weather by the use of artifi- 
cial heat will require some means of providing for the escape of the 
moisture-laden air at the top of the barn. 

A barn 32 feet wide should have two driveways extending all the 
way through the building, and doors shoidd be provided at each end 
of sufficient size to allow a team to be driven in or out Avithout dif- 
ficulty. Some barns have a greater width, thus affording room for 
three driveways. Again, in some cases, doors are provided on the 
sides opening into each bent, but this arrangement is not recom- 
mended, for it greatly increases the difficulty of rendering the struc- 
ture weatherproof. The construction of barns used for curing cigar 
leaf in the southern districts is essentiall}^ the same as that of the 
barns in northern districts, except that the ventilators usually con- 
sist of windows at intervals of about 8 feet, 2^^ to 3 feet wide and 10 



Fig. 2. — Type of barn used in sontlicrn oi,i.'ar-tobarco districts, showing the arrani,'oment 

of vpntilators. 

feet long, suspended at or near the top. A good type of l)arn 
fitted with a system of horizontal ventilators, which is used in noi-th- 
ern districts, is shown in figure 1, while figure 2 shows the typical 
barn in use in the southern districts, 

HARVESTING CIGAR TOBACCO. 

In two or three weeks after topping, the plants will begin to ripen, 
as indicated by a change in color of the leaf. Light yellowish gi'een 
flecks appear on the surface of the leaf and it snaps readily when 
folded back. To know just when the plants are ready for harvesting 
requires experience and good judgment, and much of the success in 
curing will depend on this point. Of course, all the plants do not 
ripen at exactly the same time, but usually in harvesting no attempt 
is made to single out the riper ones unless these occur in well-defined 
areas in the field. Cutting cigar tobacco in the northern districts usu- 

143 



HARVESTING CIGAR TOBACCO, 31 

ally begins about the middle of August and extends through the 
month of September, but the time may vary as much as three weeks 
in different years, depending on the season. 

The stalks are cut with a variety of implements, among which are 
stout knives with hooked blades, an ordinary hatchet, a handsaw, or 
shears with long handles. The hatchet and shears are more commonly 
used, and the latter are becoming quite popular. The handles are of 
such length that the largest stalks can be cut easily and very rapidly. 
The plants are allowed to fall over in such a way as to leave all the 
butts one way in the row and facing those of an adjoining row. This 
greatly simplifies the subsequent handling of the plants, which are 
allowed to lie on the ground until wilted to such an extent that tliey 
can be handled without much breaking of the leaves. It is customary 
to wait until the dew is nearly off the ground before beginning to 
cut the plants in the morning, and care should be taken not to'^cut 
more during the day than can be handled before night. Tobacco may 
be seriously damaged by lying on the ground overnight, especially in 
case of rain. Due care must be taken also not to allow the leaves to 
become sunburned or blistered during the hottest part of the day. 
For this reason some prefer to cut the tobacco on a cloudy day. 

The old method of stringing the plants on poles in the barn with 
twine has now been almost entirely abandoned, so that nearly all 
tobacco is cured on laths. By the old way the loose plants were 
hauled into the shed to be strung on the poles, while by the new 
method they are placed on the lath in the field. These laths are 
about twice the thickness of ordinary plastering laths, 4 feet 
in length, and generally carry 6 plants. The plants are 'attached 
to the lath in one of two ways. In the first case, a sharp-pointed 
spearhead is slipped over the end of the lath, by means of which the 
tobacco stalks are pierced through from 4 to 6 inches from the end 
and slipped on to the lath, the latter being held in a hurdle for this 
purpose, as shown in figure 3. In the second case, hooks are attached 
to either side of the lath, on which the plants are hung. On one side 
the first hook is placed 6 inches from the end, and on the other side a 
second one is fastened on 13 inches from the end, and so on, the lath 
thus carrying 6 hooks alternately arranged on either side' about 7 
inches apart. The plants can be hooked on in this wav very rapidly 
and without being damaged, with the additional advantage that they 
are very accurately spaced on the laths. 

Formerly it was the general practice to hang the laths bearino- the 
plants on scaffolds in the field for several davs before placing them 
in the barn for the final curing, but the more common way now is to 
haul the tobacco directly to the curing shed. The most "convenient 
wagon rack for this purpose, which is very simple in construction, is 



143 



32 



PRINCIPLES AND METHODS OF CURING TOBACCO. 



shown in figure 4. If the phmts are speared on to the hith, this is 
carried to the wagon as soon as filled, but if the hooked lath is used 
the i^lants are carried to the wagon and hooked on to this after it has 




■-*9, 



¥\ 




Flu. .'i. — Tobacco licld. sliowini; the nu'lluni ciiiiiloycd in spcariiiu plants on a lath, with 
the hiii'dh' used for supportiiijr the hitter during; the operation. 

been placed in position on the rack. The wagon rack for hauling to 
the barn referred to above is from -IS to IVI feet in len"th and will 




Fig. 4. — The best form of wajjon rack for hauling plants to the curing- barn. 

carry from 80 to 120 laths of tobacco. As soon as loaded the wagon 
is driven directly into the barn and the laths are hung on the tier 
poles, Avhich are about 4 feet apart. 

143 



CURING CIGAR TOBACCO. 33 

The matter of properly spacing the hiths on the poles is one of the 
greatest importance. This depends largely on the size of the plants, 
but for an average crop the laths may be hung G inches apart on the 
top tiers and this space increased downward so that on the bottom 
tiers they lie 8 inches apart. The laths are accurately spaced on the 
poles by means of a small block of the proper length, which is carried 
in the hand. Tobacco hung close together cures better in a dry sea- 
son, whereas damage from pole-sweat is correspondingly increased 
in a wet season, but as there is no means of knowing in advance 
whether dry or wet weather will be encountered the best that can be 
done is to follow a middle course. The upper tiers of the barn are 
filled first, the laths being passed up from the wagon by means of a 
fork with a long handle made for the purpose. 

For several days before filling the barn with tobacco the doors and 
ventilators should be kept open to thoroughly air out the building, 
and as soon as the barn is full all loose leaves and trash should be 
removed from the floor. It is also a good practice to spread a coat 
of lime over the floor, the object being to prevent any undue fungous 
growth which might favor the development of disease in the curing. 

CURING CIGAR TOBACCO. 

The changes in the composition and properties of the leaf which 
take place in the curing process, as well as the most favorable condi- 
tions for accomplishing these changes, have been fully discussed in 
the first part of this bulletin. The great difficulty at the present time 
lies in the fact that we have such limited means of controlling the 
conditions of temperature and humidity in the barn that we are 
largely dependent on outside weather conditions for effecting the cure. 
Nevertheless, it is important to make the best possible use of such 
means as are available for bringing about the highest development of 
the important qualities in the leaf. 

At the present time no artificial heat is used in curing cigar to- 
baccos save in case of danger from pole-sweat, when charcoal fires 
are sometimes resorted to. The only means of regulating the hu- 
midity in the barn, therefore, lies in the control of the ventilation, 
and the temperature depends solely on that of the outside air. There 
can be no doubt that eventually some practicable means of controlling 
the temperature and humidity by the use of artificial heat will be 
devised, but meantime more or less damage must necessarily result 
every year because of unfavorable weather during the curing season. 

The fundamental principle to be kept in mind during the first 
stage of the curing is to avoid too rapid drying out of the leaf. It 
is certain that many growers, in their anxiety to avoid damage from 
pole-sweat, caused by excessive moisture, injure their tobacco very 

143 



34 PEINCIPLES AND METHODS OF CURING TOBACCO. 

seriously by going to the other extreme of drying out the leaf so 
rapidly as not to allow sufficient time for those changes to take place 
which are essential to good curing. As was explained in the first 
part of this bulletin, the essential changes taking place in the curino- 
are dependent on the life activities of the leaf, and are therefore 
stopped as soon as this is killed by loss of water. Consequently, if 
the outside air is very dry the barn should be kept closed during the 
day and opened up at night. The object is to keep the moisture o1 the 
air m the barn quite high until the important changes in composition 
have taken place, as shown by the change in the color of the leaf from 
green to yellow. Warm temperatures also greatly favor these changes. 
Of course, if the outside air is quite humid the barn should be kept 
open during the day. and if it is moderately dry the ventilators 
should be opened only at the bottom. - 

As soon as the yelloAv color develops, the humidity in the barn 
should be reduced, for tlie develojiment of the brown color which 
soon follows indicates that the leaf is beginning to tlie, and this is the 
critical stage in the cure. If the humidity remains very high at 
this stage for any considerable period. ])ole-sweat will surely de- 
velop. This is to be especially feared if a season of Avarm, foggy 
weather sets in, and may soon render the entire contents of the barn 
practically worthless. Tlu' only remedy lies in the use of artificial 
heat to keep doAvn the humidity. Ventilation alone will be of little 
avail. The i)ossible methods of supplying artificial heat have been 
discussed in the first ])art of this bulletin (see p. 20). 

Entirely aside from the danger of pole-sweat, however, there are 
other important reasons why (he humidity in the barn should be re- 
duced as soon as the brown color begins to develop. The leaf dies at 
this stage and the (rue curing changes are stopped. All further 
changes in composition and properties are such as can be better con- 
trolled in the sweat room, where the ventilation, temperature, and 
humidity can be easily regulated, than in the curing shed. At the 
present time the demand is for bright colors in wrapper leaf, and the 
longer the second stage of the cure is protracted by a relatively high 
humidity the darker will the leaf be. Again, each time the tobacco 
comes into high case, after the cure is finished, the color Avill be 
further deepened. The rational method of procedure, therefore, is 
to maintain a hiah humiditv durino- the first stao-e of the cure and 
tlien, as soon as the color has developed, to dry out the leaf compara- 
tively rapidly. After the cure is finished, the tobacco should be 
prevented from coming into high case or order until it is to be taken 
down, so far as this is possible. 

The time required for completing the cure varies from six or eight 
to twelve weeks, depending on the character of the season. As has 
14a 



STRIPPING AND ASSORTING CIGAR TOBACCO. 35 

been already stated, quick curing may be depended on to give the 
best results, provided the first stage is not unduly hastened. The cure 
is finished when the midrib of the leaf has dried out so that it will 
snap when bent between the fingers. When the tobacco is ready to be 
taken down, the stalks are still quite green, and would remain so for 
many Aveeks longer. 

STRIPPING AND ASSORTINCx CIGAR TOBACCO. 

As soon as jDOSsible after the tobacco is cured, the jdants should be 
taken from the laths and the leaves stripped from the stalks. This 
can not be done, however, until after damp weather has prevailed long 
enough for the leaf to become pliable, so that it can be handled 
readily without breaking. Tobacco in this condition is said to be 
"in case" or "in order"' and weather well adapted to bringing it 
into case is frequently spoken of as a " tobacco storm." Tobacco will 
not come into order, however, if the temperature be very low, e^en 
when wet weather prevails. If the stalks have been frozen it is well 
to leave the plants hanging until the dripping stops, so as to avoid 
staining the leaf. 

As the plants are taken from the laths, they are piled in heaps on a 
floor of poles or boards, the tips all being turned inward and over- 
lapping to prevent the leaves from drying out. The leaves should be 
stripped from the stalks as soon as possible after the plants have 
been taken down, so as to avoid the heaps becoming heated. All of 
the top leaves are first stripped oif and placed in a pile designated as 
" fillers " ; then the next three or four are taken ofl' and placed in a 
second pile called " seconds." Finally, the best leaves are classed as 
" wrappers," all damaged leaves being thrown out. These different 
grades are then tied into bundles, called " hands," using a leaf as a 
binder. The bundles should be made of leaves of uniform length and 
of the same quality, the wdiole weighing about one-half pound. Care 
must be taken to exclude from the best grade all leaves showing injury 
or discoloration. After the leaves have been tied into bundles 
these are arranged in bulks on an elevated platform. These bulks 
are built by laying the bundles in two rows with all the butts outward 
and the tips of the bundles in the two rows overlapping somewhat. 
The bulk is covered with oilcloth or other suitable material to prevent 
the leaves from drying out. They must be carefully watched to pre- 
vent their becoming heated, which is particularly liable to occur if 
the leaf is packed down too moist. If heating does occur, the piles 
must be torn down, and rebuilt after the bundles have been shaken 
out. 

Before the leaf is ready for the manufacturer it must undergo a 
process of fermentation, commonly spoken of as " sweating." To 

143 



36 PRINCIPLES AND METHODS OF CURING TOBACCO. 

carry out this process successfully requires a thoroughly equipped 
plant with adequate facilities for controlling ventilation, tempera- 
ture, and humidity, so that as a rule the growers sell their leaf in the 
bundle to the dealers who make a business of carrying on the fer- 
mentation on a large scale. The tobacco must also be very carefully 
assorted into grades, but the dealer generally prefers to do this him- 
self in order to secure greater uniformity ; and the grower, unless 
thoroughly experienced in the business, does w^ell not to attempt the 
work of grading. This work of grading and fermenting cigar-leaf 
tobacco has become a highly specialized industry, quite distinct from 
the curing process, properly speaking, and so does not require further 
consideration here. 

SHADE-GROWN CIGAR-WRAPPER LEAF. 

In recent years the growing of Cuban and Snmatran types of cigar- 
wrapper leaf under artificial shade has become a very important 
industry in portions of southern Georgia and western Florida and in 
the Connecticut Valley. The details of harvesting and curing this 
leaf differ in some important points from those enq:)loyed for the 
ordinary types grown in the open air, and therefore require some 
further consideration. The barns, howcAer, are of the same construc- 
tion as those used in curing the tobacco grown in the open air. 
except that, since the leaves are picked from the stalk in harvesting, 
the tier poles are only 2^ feet apart vertically. The ordinary type 
of barn can therefore be very readil}^ converted into one adapted to 
the shade-grown leaf by simph' placing additional tiers of poles 
midway between the tiers already in position. A l)arn will hold 
about the same quantity of tobacco whether harvested on the stalk 
or by picking the leaves. 

As has just been stated, all shade-grown leaf is picked from the 
stalk in harvesting, and this is done to insure the maximum yield of 
high-grade wrappers. Tobacco grown under shade does not show the 
ordinary signs of ripening so clearly as does that grown in the open 
air. and, moreover, to get the best results it is necessary to harvest the 
leaves before they would ordinarily be considered fully ripe. When 
ready for harvesting the lower three or four leaves are picked by 
hand and packed in baskets lined with burlap. The baskets, as soon 
as filled, are hauled to the curing shed, those exposed to the sun being 
covered with burlap to avoid injury to the leaves. A convenient rack 
for hauling the baskets to the barn is shown in figure 5. The field is 
gone over three or four times before all the leaves are harvested, the 
object being to pick all of them when at just the right stage of 
maturity. 

143 



SHADE-GROWN CIGAR-WRAPPER LEAF. 



37 



In southern districts the leaves are strung on cords attached at 
each end to hiths. These Laths are of the same length but smaller 
than those used for curing tobacco on the stalk. A notch is made 
with a saw in each end of the lath and one end of the cord is drawn 
into one of these notches, wrapped around the end of the lath, and 
again drawn into the notch. The leaves, 30 or 40 in number, are then 
strung on the cord by means of a large steel needle and the free end 
of the cord is attached to the second end of the lath in the same man- 
ner as in the first case, care being taken to draw the cord sufficiently 
tight to prevent too much sagging. The leaves are strung on the cord 
in pairs, as it were, so that the front surfaces of each pair are face to 
face and the backs face the backs of adjoining pairs. This is done to 
prevent the leaves from sticking together as they curl up from loss of 
water. 




Pi(!. 5. — A very convenient wagon rack for haulinij; baskets of ijickcd 

barn. 



'Uvos to the curiii; 



In the Connecticut Valley some growers string their tobacco on 
cords in the manner just described, but a second method of hanging 
the leaA'es is coming into extensive use. Small, slender wire nails are 
driven through each side of the lath at an upward angle and at in- 
tervals of 2 inches, beginning 4 inches from the ends. This provides 
40 spikelets in all, 20 on each side, and on each of these one leaf is 
hung. The leaves are all hung so as to face outward. In this case 
the leaves hang with their flat surfaces parallel to the long axis of 
the lath, while those strung on cords hang with their surfaces at 
right angles to this axis. Each of these methods of stringing the 
leaves possesses points of advantage, and it is difficult to determine 
just which is the better one. The work of stringing the leaf is 
usually done by girls or boys, some of Avhom develop remarkable 
dexterity. The laths carrying the leaves are hung on the tier poles 

143 



38 



PRINCIPLES AND METHODS OF CURING TOBACCO. 



at intervals of 4 to G inches, dependina" on the size of leaf. The 
method of arranging- the laths on the poles in the barn is shown in 
figure G. 

MANAGEMENT OF THE CURING BARN. 

The changes in composition of the leaf are doubtless of the same 
character as those which take place in curing tobacco on the stalk, 
but less complete than in the latter case. The two important differ- 
ences in the two cases are that the picked leaves cure much more rap- 
idly than those left on the stalk, and the conditions in the barn as to 
humidity and temperature are more easily controlled. Both of these 




Pig. (5. — The interior of a cigar-tobacco barn, showing the arrangement of tier poles and 
the method of hanging picked leaves. 

facts are due to the circumstance that the stalks, which contain so 
much water and give up this water so slowly, are not placed in the 
barn Avhen the leaves are harvested by picking. 

During the first stages of the curing due care must be taken to 
prevent the tobacco from drying out too rapidly. If the weather be 
very dry, the ventilators should be kept open for only a few hours 
in the morning. The picked leaves are whipped about by the wind 
more readily than those cured on the stalk, and hence the venti- 
lators must be closely watched in windy weather to prevent injury to 
the tobacco from this source. As soon as the brown color develops, 

143 



BURLEY TOBACCO. 



39 



the leaf may be allowed to dry out rather rapidly. The leaf proper 
cures down in a short while, but a much longer time is required for 
completely drjdng out the stems. The picked leaves are subject to 
pole-sweat at the critical stage, the same as when cured on the stalk, 
but of course the danger period is much shorter in the former case. 
Under favorable conditions the curing will be completed in from four 
to six weeks. 

After the tobacco is completely cured it is allowed to hang in the 
shed until the weather becomes sufficiently moist to soften the leaf 
so that it can be handled without breaking, when it is taken down and 
tied into bundles. If the leaves are strung on cord, this is cut from 
the lath, the leaves slipped to its center, and tied with the free ends. 
In this case the entire contents of the barn may be taken down before 
the tobacco is removed from the laths, these being piled in bulks on a 




Fig. 7. — Type of tobacco barn used in the lUirley district of Kentucky. 

temporary board floor. If the leaves are hung on tlie nail laths they 
must be stripped off from these as fast as they are taken down and 
tied into bundles in the same way as when cured on the stalk. 

BURLEY TOBACCO. 

Burley tobacco requires a fertile limestone soil for its highest 
development. The bulk of the crop is grown in the district embraced 
in the States of Kentucky and Ohio which borders on the Ohio River. 
Burley tobacco is also grown in considerable quantities in parts of 
Tennessee and West Virginia and in a small way in several adjoining 
States. Like cigar tobaccos, it is cured without the use of artificial 
heat except when there is danger of injury from house-burn, or pole- 
sweat. There are many types of barns in use for curing, ranging 
from the small crude log structure to the most approved modern 

143 



40 PRINCIPLES AND METHODS OF CURING TOBACCO. 

frame building with ample facilities for controlling the ventilation. 
These modern barns are essentially the same as those used in the 
cigar-tobacco districts, Avhich have already been discussed, and so 
need not be further described here. An approved type of barn is 
shown in figure 7. 

IIARVESTIXG BI^RLEY TOBACCO. 

When fully ripe the plants are harvested by first splitting the stalk 
with a knife down about two-thirds of its length, then cutting it off 
near the ground and placing it astride a stick. The sticks are 4 feet 
4 inches long and carry five or six plants, depending on their size. 
These are loaded on a rack similar to that shown in figure 4. hauled 
to the barn, and hung on the tier poles at intervals of about 12 inches. 
Some growers prefer to hang the tobacco on scaffolds in the field for 
two or three days, so as to allow it to become thoroughly wilted before 
housing it. In this case it can be safely hung considerably closer 
together in the barn than when carried directly from the field to the 
barn. 

Cl i;iN(; Ul lUJ'.Y TdHACCO. 

The method of curing is the same as for cigar tobacco, and the 
changes which take place are of the same kind. When cured, how- 
ever, the color is yellow to red instead of the characteristic brown 
of cigar leaf. If the weather is dry, the barn should be kept tightly 
closed during the day and open at night, while in wet weather thor- 
ough ventilation is required. If the weather is very damp during the 
curing period, the leaf cures doAvn too dark. Some growers use small 
charcoal fires to dry out the barn when pole-sweat sets in. From 
five to eight weeks are usually required for completing the curing 
process. 

ASSORTING AND PACKING lURI.KY TOBACCO. 

^Y\\en taken down from the barn, the leaves are stripped from the 
stalk and assorted. The usual grades are (1) sand leaves, (2) trash, 
(3) lugs, (4) bright leaf. (5) red leaf, (G) tips. The three first- 
named grades are used principally for smoking tobaccos, the bright 
leaf for plug wrappers, and the red leaf and tips for plug fillers. 
These different grades are tied into bundles containing from 10 to 
20 leaves and bulked down. The tobacco may then be packed at once 
into hogsheads or it may be allowed to remain in the bulk all through 
the winter, in which case it is hung up in the barn in the spring, 
where it undergoes a sort of sweat or fermentation. In either event it 
is packed under pressure into large hogsheads, which when filled 
hold from 1,000 to 1,500 pounds, and it is then ready for transporta- 
tion to market. 

143 



CONSTRUCTION OF BARN FOR YELLOW TOBACCO. 41 

SUN-CURED TOBACCO. 

In a few counties of Virginia in the vicinity of Richmond a type 
of tobacco is produced which is much esteemed as a phig filler. This 
tobacco is cured by a modification of the air-curing process, which 
seems to develop its characteristic properties. After harvesting it is 
hung on a scaffold in the field, exposed to the sun until nearly cured, 
and then carried to the barn, where it hangs until ready for stripping. 
If the harvesting is followed by a period of cloudy weather, the 
tobacco, of course, receives little or no sunshine, and the curing ap- 
proaches more nearly that of the cigar and Burley types. 

YELLOW TOBACCO. 

The yellow type of tobacco can be successfully grown only on light 
sandy soils which are, in general, poorly adapted to the production 
of most other crops. The importance of the character of the soil is 
well illustrated by the fact that small areas on a farm may produce a 
bright yellow leaf of the finest quality, while other portions of the 
same farm will grow only a heavy dark type, suitable for export. 
The bulk of the bright yellow tobacco is grown in North Carolina 
and in portions of Virginia, South Carolina, and Tennessee. 

Equally as important as the character of the soil is the manipula- 
tion of the curing process. No other type of tobacco requires so 
much skill, experience, and good judgment for successful curing. 
Lack of attention even for a few hours during the curing may prac- 
tically ruin the entire contents of a barn. The distinctive feature of 
the method used for curing this class of tobacco is the use of flues for 
conducting artificial heat into the barn in such a Avay that the smoke 
and gases from the fire do not come in contact with the leaf. The 
heating is kept up continuously from start to finish, thereby greatly 
shortening the curing period. Thus, except under unusually adverse 
conditions, the curing proceeds at a given rate practically independent 
of outside weather conditions. 

CONSTRUCTION OF THE liARN FOR CaiRING YELLOW TOBACCO. 

The type of barn most widely used in curing yellow tobacco is 
comparatively simple in construction and is characterized by its small 
size. These barns are generally, but not always, built square and 
vary from 16 to 24 feet in width, inside measurement. It is neces- 
sary that the inside width of the barn be some multiple of 4 feet, 
since this is the distance between the tier poles which extend across 
the barn lengthwise and receive the sticks on which the tobacco is 
hung. The first set of tier poles is placed 9 feet above the ground 
and each succeeding set 2 feet 8 inches to 3 feet higher. The smaller 

143 



42 



PRINCIPLES AND METHODS OF CURING TOBACCO. 



sized barns are usually built IT feet high to the eaves, and therefore 
contain four sets of tier poles, while the larger ones are frequently 
built 20 feet high and contain five sets of tier poles. Additional 
tiers may be placed in the roof. 

The barns are generally built of logs, but many framed structures 
have been erected in some sections in recent years owing to the in- 
creasing scarcity of timber. When logs are used, the cracks are either 
chinked with mud or closed with lime mortar. A typical loo- barn 
is shown in figure 8. If framed barns are built, tlie cracks should 
be battened with thin strips of boards. Ventilation is usually se- 
cured by leaving openings around the bottom of the barn and by 
cutting small windows in the gable ends near the roof, which can 
be closed when desired. Many liarns contain so uianv cracks and 




Fig. 8.- A t.viiical lug baru ,,. a ^ i,_ ,,n,,w tobacco, showing the vontilntor in the 

sal>le and the outside portions of the heating system. 

crevices, especially about the roof, tliat they require no special ven- 
tilators, but such barns are poorly adapted to curing yellow tobacco. 

As explained in the first part of this bulletin, it is important to 
keep the barn tightly closed during the first stage of the curing, 
while in the sec(md stage it is even more important to have ample 
ventilation. These requirements can only be met by building the 
barn as tight as practicable in the first instance and then providing 
a system of ventilators which can be opened and closed at will. Any 
reasonable outlay to secure these ends will be amply repaid, both 
in saving of fuel and in obtaining a finer (juality of cured leaf. 

The heating system consists of a series of sheet-iron flues leading 
from small furnaces placed at one end of the barn. The arrange- 
ment of the flues is comparatively simple, but is variously modified 
in different sections of the flue-curing belt. One of the best arrange- 

143 



CONSTRUCTION OF BARN FOR YELLOW TOBACCO. 



43 



ments for the larger sized barns is that shown in figure 9. The fur- 
naces (fig. 9, F, F) are built of stone or brick and are usually 
about 18 inches wide and 20 inches high, inside measurement. The 
tops are arched and the walls are made sufficiently thick to avoid 
all danger of igniting the walls of the barn. The furnaces are built 
from 4 to 5 feet long, and project on the outside about one- fourth 
of their length. The flues are made in sections similar to ordinary 




Fig. 9. — Sketch showing the arrangement of furnaces and tlues in a barn adapted for 
curing yellow tobacco : F, F, brick furnaces : A. B, C. D, sheet-iron flues. 

stovepiping and are from 10 to 15 inches in diameter. These flues 
are fitted into the ends of the furnaces at A, A, and extend thence 
across the barn to B, B, where they turn at right angles and, con- 
tinuing to C, C, they once more turn at right angles and finally pass 
outward through the wall at D, D. The flues are slightly inclined 
upward throughout their length and pass out through the barn wall 
about 3 feet higher than the mouth of the furnace. A smokestack 

143 



44 PRINCIPLES AND METHODS OF CURING TOBACCO. 

3 or 4 feet in heioht, the upper end of which is provided with a 
hood, is fitted to the outer end of the flue. 

This arrangement of the flues is modified in a variety of ways. 
The two flues may be united (see fig. 9, C, C), whence a single arm 
returns to the side of the barn from which the furnaces enter, thus 
giving three lengths of pipe across the barn instead of four. In 
the smaller barns a single furnace placed in the center of one end 
is often made to supply the necessary heat. In this case a single 
flue leads across the barn and then branches at right angles, each 
arm returning along the side Avails, thus simply reversing the last- 
described arrangement. Whatever arrangement is used, the flues 
should in no case be placed within 2 feet of the walls of the barn, 
and they nnist, of course, be surrounded Avith sheet tin or other suit- 
able material at the point where they pass through the wall. 

HARVESTING YELLOW TORACCO. 

There are tAvo general methods of harvesting yelloAv tobacco, in 
one of Avhich the entire plant is cut. Avhile in the other the leaA'es are 
stripi)ed oil' as fast as they ripen. As a I'ule. the latter method is 
generally used in the ncAver districts, while the practice of cutting 
the entire plant has many adherents in the older districts. The merits 
of these tAvo methods of harvesting have already been discussed in 
Part I (p. 10). Whichever of the two methods is used, the leaf 
should be riper before housing than is the case Avith almost any other 
tobacco. The entire ])lant should have a yelloAvish green cast, Avhile 
the leaf should shoAv numerous flecks of a lighter tint in Avhich the 
yelloAV is more j^ronounced. To obtain the best colors in curing 
recjuires that the tobacco be harvested at just the right stage, and 
here experience and good judgnuMit are essential. 

When the method of [)iclving the leaves from the stalk is folloAved, 
three or four of the bottom leaves are stripped off at the first harA'est. 
This process is rei)eated three or four times till all of the leaves haA'e 
been harvested. The leaA'es are placed in baskets and hauled directly 
to the barn or to a temporary brush arbor, Avhich protects them from 
the sun, and are then hung on sticks. There are tAvo Avays of attach- 
ing the leaves to the sticks, Avhich are generally cut 4 feet 4 inches in 
length. In the one case a stout cord is fastened to one end of the 
stick and draAvn into a notch Avhich has been previously saAved in the 
end of the stick. A few inches from this end the cord is passed 
once around a bunch of three or four leaA^es. Avhich Avill thus hang 
to one side of the stick. The cord is then draAvn to the opposite side 
of the stick and similarly passed around a second bunch of leaves, 
the Avhole process being repeated till the stick is full. Each stick 

143 



CUEING YELLOW TOBACCO. 45 

Avill thus carry from 20 to 30 bunches, arranged alternately on either 
side. Another method consists in stringing the leaves on a series of 
wires, about 10 inches long, which are attached to the stick with 
small staples at intervals of about 8 inches, as shown in figure 10. 
These Avired sticks carry about the same number of leaves as those 
on which cord is used. They possess a serious disadvantage in that 
the tobacco must first be stripped off before it can be bulked down. 

When the entire plant is harvested the stalk is first split from the 
top down to near the bottom leaves and then cut off near the ground. 
The plants are then inverted and placed astride a stick, each stick 
receiving (> to 8 plants. The tobacco is loaded on the wagon in 
"• coops,"' or square heaps, with the tips of the plants toward the cen- 
ter, or a better Avay is to haul it to the barn on a rack, such as is 
shown in figure 4. The sticks are hung from 8 to 12 inches apart on 
the tier poles. 

CURING YELLOW TOBACCO. 

The flue-curing process is the only method of curing tobacco in 
use at the present time which affords the means of controlling the 




Fig. 10. — Stick with wires used in tlie .ycllnw tobacco districts for hanging picked leaves 

ill I he curing baro. 

temperature and humidity in the barn. The nature of the changes 
in composition and jn-operties of the leaf which takes place in the 
process of curing and the relation of temperature and humidity to 
these changes have been discussed in the first part of this bulletin. 
A large number of formulas for curing yellow tobacco have been 
used with more or less success, but the universal experience has been 
that any fornuda will require some modification for every curing 
made. The principal reason for this lies in the fact that all these 
fornndas are based solely on temperature, which is only one factor. 
To the experienced grower the thermometer is a valuable aid, but 
the condition of the tobacco is watched as closely as is the ther- 
mometer. 

The barn should be completely filled in one day, and when this 
is done a thermometer is hung on the lower tier and near the center 
of the barn. Small fires are started in the furnaces and a very mod- 
erate temperature maintained until the leaf is thoroughly yellowed. 
During this period, from tAventy-four to thirty-six hours, the barn 
should be kept tightly closed. The yellowing may be accomplished 
at any temperature between 80° and 120° F., and it is well to start 
with the lower temperature and gradually raise it up to 110° or 120° 
F. at the completion of the process. 

143 



46 PKINCIPLES AND METHODS OF CURING TOBACCO. 

The comi^letioii of the yellowing process ends the first stage of 
the curing, and then begins the critical period commonly spoken of 
as '' fixing the color." The sole object at this stage is to remove the 
moisture as fast as it is given off by the leaf, and plenty of ventila- 
tion is essential to success. The tobacco should be closely watched, 
and if particles of water begin to show on the surface of the leaf 
more ventilation is required. Care should be taken that the tem- 
jDerature does not fall, and the best results are obtained when it is 
gradually increased throughout this phase of the curing until 130° to 
135° F. is reached. If insufficient heat is supplied and, more im- 
portant still, if there is not ample ventilation, the leaf will redden 
or " sponge." If the heat is increased too rapidly while the leaf 
is still full of sap, a greenish black discoloration will develop, which 
is known as " scalding " or "" blistering.'" The nature and causes of 
these troubles have been discussed in Part T (p. 24). The remedy 
lies in a moderate and carefully regulated tempei-ature. together with 
l^lent}^ of ventilation. 

The temperature should be maintained at from 130° to 140° F. 
until the leaf is completely dried out. which will require about ten 
to eighteen hours after the c()mi)letiou of the yellowing process. All 
danger from sponging or scalding is now })ast. and it only remains 
to dry out the stems. The xentilators are now closed and the tem- 
perature raised up to IC).") or 170° F. at the rate of about 5 degrees 
an hour. This latter temperature is maintained till all stems are com- 
pletely dried out. Some raise the temperature as high as 190° and 
even 200° F.. but this greatly increases the danger of burning up the 
barn and contents, an accident whicli is by no means of rare occur- 
rence. "\Mien the tobacco is to be taken down the barn is left open 
during the jn-eceding night so that the leaf may absorb sufficient 
moisture to bring it into condition for handling. If the leaf can 
be folded in the hand without breaking the stem it is in proper con- 
dition to be taken down without injury. 

FIANULIXC; VKLLOW TOBACCO AFTER CURING. 

When taken down the tobacco is carried to the packing house, 
where it is bulked down without removal from the sticks. The bulks 
are built up with all the butts pointing outward and the tips over- 
lapping in the center. The heaps are usually made 4 or 5 feet 
high and may be of any convenient length. In order to avoid injury 
from mold the bulks should be torn down at the end of a Aveek and. 
if desired, rebuilt. This treatment greatly improves the color of 
the leaf and especially assists in bleaching out the green remaining 
in the leaf after the curing. It frequently happens that the entire 
contents of a liarn showing a decided greenish cast will come from 
the bulk with a beautiful clear lemon-j-ellow color, provided the 

143 



HEAVY EXPORT TOBACCOS. 47 

green has not been set by drying ont the leaf too rapidly in the first 
stage of the curing. 

When the bleaching process has been completed the leaves are care- 
fully assorted into from six to ten grades, based mainly on color 
and freedom from holes or spots. Yellow tobacco is classified on the 
market into (1) wrappers, consisting of the most perfect leaves; (2) 
cutters, leaves deficient in color and inferior to wrappers; (3) smok- 
ers, bottom or sand leaves and others bruised or torn and lighter in 
body than cutters; and (4) fillers, everything not included in v.rap- 
pers, cutters, or smokers. Each of these four classes is subdivided 
into two or more grades. The finest grade of wrappers is bright 
lemon-yellow in color and composed of leaves free from imperfec- 
tions and 250ssessing sufficient toughness and elasticit3\ The next 
best grade is orange-3'ellow in color, and then comes the light reddish 
brown grade, known as " mahogany wrappers." 

Market prices are greatly influenced by the care and skill used in 
grading yellow tobacco, and this work requires experience and the 
ability on the part of the assorter to accurately classify colors. Each 
grade is tied into small bunches, or "' hands,'"' and the leaf is then 
ready for market. If the market conditions are unfavorable the 
tobacco may be bulked down and kept in this way until placed on the 
market. 

HEAVY EXPORT TOBACCOS. 

The method in use for curing the heavy export type of leaf is a 
sort of combination of the air-curing and the flue-curing processes, 
although historically it is perhaps the oldest of all the methods of 
curing tobacco. The first stage in the curing is carried out without 
the use of artificial heat, and is therefore identical with the air-curing 
method, as applied to the cigar and Burley types. In the later stages 
small fires are kindled on the floor of the barn and the smoke is 
allowed to pass up through the tobacco, thereby imparting to it a 
characteristic odor, as well as materially augmenting its keeping 
qualities. 

The old type of barn used for curing export tobacco is very similar 
to that in general use for curing yellow tobacco. It was built of logs, 
the cracks being daubed with mud. These barns were small in size, 
but were generally built high enough to contain five sets of tier poles. 
In recent years the log barns have been partly replaced by more mod- 
ern frame buildings of much larger size. These are provided with 
large doors opening into passageways which lead through the build- 
ing, thus allowing a loaded wagon to be drawn directly beneath the 
tier poles. These tier poles are arranged at intervals of about 3 feet 
10 inches horizontally and 3 feet vertically, the first set of poles being 
8 or 9 feet above the ground. 

143 



48 PRINC'TPLES AND METHODS OF CURING TOBACCO. 

HARVESTIN<J EXPORT TOBACCO. 

The class of heavy export tobacco as a rule matures considerably 
later than the bright tobacco, owing chiefly to the character of the soil 
on \\-hich it is grown. By allowing it to stand in the field for several 
weeks after topping there is a decided gain in size and weioht of the 
leaf. When ready for harvesting the leaves droop, they lire thick 
and heavy, mottled with yellow flecks, and break readily when folded 
between the fingers. As a rule, the plants do not all ripen at the same 
time, so that it is necessary to make two cuttings. It is not desirable 
to harvest the tobacco immediately after a heavy rain, for the reason 
that much of the gummy matter secreted by the leaf is dissolved by 
the water, resulting in a considerable loss of weight. 

In harvesting, the stalk is first split down to^itliin a few inches 
of the bottom leaves and then severed near the ground. As soon as 
sufficiently wilted to be handled without brealdng the leaves, the 
stalks are placed astride a stick and are then ready for carting to the 
barn. The sticks upon which the plants are hung are usually 4 feet 4 
inches in length, and each stick carries from six to tenplants, depend- 
ing on their size. The sticks carrying the i)lants are piled in squares 
on the floor of the wagon for hauling to the barn, with the tips of the 
plants pointing to the center: or a better way is to suspend the sticks 
on a long rack, as shown in figure 4, They are hung on the tier poles 
at intervals of from 7 to 10 inches. Some growers prefer to ha no- the 
tobacco on scafi'olds in the field for several days before housing, in 
which case the plants are placed closer together in the barn. 

CURINC EXPORT TOBACCO. 

No heat is used for the first three or four days of the curing period, 
for if applied at this stage the leaf would dry out too rapidly. It is 
important to avoid this drying out of the leaf before the proper colors 
have been developed and other important changes effected. In this 
case the leaf would be starchy and lifeless to the touch, deficient in 
those substances Avhich impart to it toughness and elasticity. After 
the third or fourth day slow fires are started on the floor of the barn 
and the temperature maintained at 00° to 95° F. for about twenty- 
four hours. This moderate heat greatly facilitates the yellowing of 
the leaf. As soon as this is accomplished the temperature may be 
slowly increased till 125° or 130° F. is reached and held at this point 
till the leaf tissue is pretty well dried out. The fires are then allowed 
to die out, so that the leaf may again become pliable by the flow of 
sap from the stalk and stem. 

This process of alternate drying out and softening of the leaf is 
repeated during scA-eral weeks, until the stem and leaf are both com- 
pletely cured. During the first stages of the firing, when the tobacco 

143 



HANDLING EXPORT TOBACCO. 49 

is still full of sap, too much heat umst be guarded against, else por- 
tions of the leaf will be discolored by "" scalding,'' as in the case of 
fine-curing yellow tobacco. If the tobacco remains hanging in the 
barn for any considerable length of time after the curing is com- 
pleted, slow fires should be started during periods of wet weather to 
prevent injury to the leaf from molds and also to prevent too much 
darkening of the color. Frequently the tobacco is improved by bulk- 
ing it down Avithout removing it from the sticks, as already described 
for yellow tobacco. 

HANDLING I<:XPORT TOBACCO. 

When the tobacco after being thoroughly cured has become pliable 
by the absorption of moisture during a damp season the plants are 
removed from the sticks and piled in heaps so arranged that all the 
butts face outward. Beginning at the bottom of the plant the leaves 
are stripped off and tied into small bundles according to grade. The 
poorest grade, composed of badly damaged and torn leaves, is known 
as " lugs." Those leaves which are inferior in color or damaged, but 
better than lugs, are designated as '' seconds," while the renuiining 
sound leaves are classed as " good." These good leaves are further 
subdivided into several grades, based largely on evenness and depth 
of color. It is also important to assort the leaves according to size, 
so that the same bundles shall not contain both long and short leaves. 
The finest grades are usually put into bundles of only five or six 
leaves, while the bundles of poorer quality may contain eight or ten 
leaves. 

The profits in growing shipping tobaccos depend in large measure 
on the skill and care used in assorting and handling the cured prod- 
uct. This class of leaf is sold by sample, and a few badly graded 
leaves drawn for this purpose will necessarily lower the valuation of 
the entire, lot represented by this sample. Care must also be taken 
that the tobacco does not contain too much moisture when packed 
down, for in this case it will be damaged by mold as soon as warm 
weather sets in. Tobacco offered on the market in this condition will 
only be taken by those prepared to rehandle it. It is far better to 
'' reorder " such tobacco by again hanging it in the barn until well 
dried out. It is then ready for taking down again as soon as favor- 
able weather for handling develops. To preserve them in fit condi- 
tion for packing, the bundles are then bulked down on an elevated 
platform and the bulks covered with blankets. 

In a few weeks after being bulked down the tobacco is packed, or 
" prized," into large casks. There is nnich variation in the dimen- 
sions of casks used in different localities. The bundles are packed 
in the hogsheads in closed or cylindrical form instead of spreading 
out the tips of the leaves, as is done with some types of tobacco. A 

143 



50 PRINCIPLES AND METHODS OF CURING TOBACCO. 

screw press is vised in packing the casks under the proper pressure. 
These casks or hogsheads contain from 1,000 to 2,000 or more pounds 
of leaf, depending on the grades, the best grades being packed in 
smaller quantities. The casks are transported to the warehouse, 
where samples are drawn by sworn inspectors under state regula- 
tion, and the tobacco is sold at auction. 

PERIQUE TOBACCO. 

Although produced in rehitively very small quantity, the type of 
tobacco known as *" Perique " is specially interesting on account of the 
peculiar methods used in curing and preparing it for market. It is 
grown only in St. James Parish, La. On account of the soil and 
climate in this region, the tobacco grows very rapidly and is har- 
vested in early summer. The plants are cut during the middle of 
the day and carried directly to the curing shed. They are suspended 
from ropes by means of short pieces of cane driven into the stalks 
at an angle near the basal end so as to form a liool^. 

Xo artificial heat is used in curing Perique tobacco. As soon as 
the leaf tissue assumes a brown color the leaves are stripped from 
the 2)lant before the stems have cured. The leaves are stripped from 
the plant at intervals of a few days, oidy three or four being taken 
at a time. The leafy portion is stripped from the green stems and 
made into loose rolls which are i)a('ke(I into a small. s(|uare box hav- 
ing a capacity of oO pounds. A pressure of several thousand pounds 
is brought upon the tobacco in the box and maintained for twenty- 
four hours. The rolls are then opened out and exposed to the air till 
the expressed saj) has again been absorbed. The tobacco is again placed 
under pressure and the Avhole process repeated every twenty-four 
hours for a i)eri()d of ten days. After this the manipulation is re- 
peated at increasing intervals for several weeks till the leaf is fully 
cured and has assumed a black color. 

Perique tobacco is generally spoken of as being "cured in its 
juices." and vmder this method of curing acquires a peculiarly fine 
aroma. The sap is repeatedly expressed from the leaf and thereby 
subjected to the oxidizing action of the air. This affords a complete- 
ness of fermentation which is not attained in any of the other meth- 
ods of curing. 

Perique tobacco is assorted into wrappers, fillers, and smokers. To 
prepare it for market the cured product is put up into 4-pound 
cylindrical rolls called " carottes." These are prepared by spreading 
a layer of the leaves, which have been opened out, upon a piece of 
cloth and covering them with a second cloth. The whole is then 
rolled into a hollow cylinder and the ends tucked in and tied. A 
coil of rope is next tightly wound around the roll by means of a wind- 
lass and the carotte is then ready for market. 

143 



INDEX. 

Page. 

Air-curin<j tobacco, effects of heat and ventilation 18-20 

process, description of stages 12-22 

modifications 21-22 

saturation point at different temperatures 20, 23 

water capacity at different temperatures 20, 23 

Assorting Burley tobacco 40 

cigar tobacco 35-36 

export tobacco 49 

yellow tobacco 47 

Barn, tobacco, for curing cigar types, description 27-30 

heavy export types, description 48-49 

yellow type, description 41-44 

heating system for flue-curing 42-44 

Bams, tobacco, construction 27-30, 41^4 

log, descriptions 42, 47 

Bleaching yellow tobacco , 46-47 

Bulking Burley tobacco 40 

cigar tobacco 35 

export tobacco 49 

yellow tobacco 46-47 

Burley tobacco. See Tobacco, Burley. 

' ' Garottes, ' ' Perique tobacco, preparation 50 

Cigar tobacco. See Tobacco, cigar. 

Color, changes in curing tobacco 8, 13-15, 22-23, 24, 34 

fixing in flue-curing yellow tobacco 24, 46 

requirements, Burley tobacco 21 

different types of tobacco 9-10, 21, 34 

cigar tobacco - 34 

Coloring, tobacco leaf, relation to time of harvesting 9-10 

Connecticut Valley, tobacco growing under shade 36 

Cuban tobacco. See Tobacco, Cuban. 

Curing shade-grown cigar-wrapper leaf, management of barn 38-39 

tobacco, air process, stages and modifications 12-22 

Burley 12-21, 40 

changes in composition and properties of leaf 8-9, 13-15, 22-23 

cigar 12-21, 33-35, 38 

export 48-49 

flue process, description and management 22-25 

leaves after picking compared to curing on stalk 10-12 

Perique ' 50 

practical methods as applied to various types 27-50 

principles 7-25 

with open fires, description, effects on leaf 25 

yellow 41-47 

51 
143 



52 PBINCIPLES Ax\D METHODS OF CUEING TOBACCO. 

Cutting tobacco, implements ^^^-|' 

Dampness. See Humidity. 

Discoloration of tobacco caused by pole-sweat 17 

Dryness, injury to tobacco in curinR. .. Va tq oa 

ii^vaporation, check by humidity, injury to tobacco I7 19 20 34 

Export tobacco. See Tobacco, export. ' ' ' 

Fire-curing tobacco, description and effects on leaf 95 

Fires, open, use in curing tobacco 9- 

Florida, western, shade-tobacco growing o^ 

Flue-curing process, tobacco, description and management 22-25 41-46 

Flues, tobacco barn, arrangement ' 49,44 

Georgia, southern, shade-tobacco growing 3g 

Green coloring matter in tobacco, changes in curing 13, 14 22 24 25 

Handling export tobacco ' ' 49I5Q 

Harvesting Burley to])acco .q 

cigar tobacco 30-33 

export tobacco ^o 

Perique tobacco ^q 

shade-grown cigar-wraj>])er leaf 36-37 

yellow tobacco 44_j5 

Heat, artificial, application in air-curing tobacco 18-21 33 40 

Heating system, tobacco barn for flue-curing 42-44 

House-burn. See Pole-sweat. 

Humidity conditions, tobacco curing, control 16 18-20 23 33 34 

injury to tobacco j^g 34 

Imiilemeiits for harvesting cigar tobacco 31-33 37 

Introduction to bulletin 7_g 

Kentucky, Burley tobacco growing 39 

Leaf, tobacco, coloring, relation to time of harvesting 9_10 

composition and ])roi)erties, changes taking plac-e in curing 

process 8-9, 13-15, 22-23 

curing, comparison with curing on stalk 10-12 38 

texture, relation to time of harvesting 10 

tissue, starvati(m in curing I3 15 

Leaves, tobacco, injury from bruising I3 17 

Log barns for tobacco, descrii)tion 42, 47 

Louisiana, Perique l()l)acco growing 50 

' ' Lugs, ' ' export tobacco, damaged leaves 49 

Marketing export tobacco 49 

Moisture, effect on color of cured tobacco 14-15 

North Carolina, yellow tobacco growing 41 

Ohio, Burley tobacco growing 39 

Packing Burley tobacco 40 

export tobacco 49 

Perique tobacco. See Tobacco, Perique. 

Plug-filler tobacco, production in Virginia 41 

wrappers, curing on stalk 12 

Pole-sweat, tobacco, causes and conditions ior spread 16, 17, 20, 34 

organisms, effects 17-18 

remedy 18 

Priming method of curing tobacco, comparison to curing on stalk 10-12, 38 

shade-grown cigar-wrapper tobacco 36 

yellow tobacco. ... 44 



INDEX. 53 

Page. 

Prizing export tobacco 49 

Rack, wagon, for harvesting cigar tobacco 32, 37 

Reddening leaf tobacco, prevention 24, 25 

Ripeness, tobacco, signs 9, 30, 3(i, 44, 48 

Ripening of tobacco, color and texture changes 9-10 

Scalding tobacco, cause and avoidance 24, 46, 49 

Shade-grown cigar- wrapper leaf, harvesting and curing 36-39 

Smoke, effect on tobacco leaf 25 

cured tobacco, keeping qualit}' 25 

Soils, limestone, adaptation to growing of Burley tobacco 39 

yellow tobacco 41 

South Carolina, yellow tobacco growing 41 

" Splotching" of tobacco, cause and avoidance 24, 46, 49 

" Sponging" of tobacco, cause and avoidance 24, 46, 49 

Stalk-curing tobacco, comparison with leaf-curing 10-12, 38 

Steam heat, application in air-curing tobacco 21 

Stringing leaf tobacco, methods 31, 37, 44, 48 

Stripping cigar tobacco 35-36 

Sumatra tobacco. See Tobacco, Sumatra. 

Sun-cured tobacco, production in Mrginia 21-22, 41 

Sweat, cold, in ciu'ing tobacco, injury 15 

pole. See Pole-sweat. 

Temj^erature, control in flue-curing yellow tobacco 24 

fatal to life of tobacco 15, 24 

tobacco curing, control 15-17, 18-20, 23, 34 

Tennessee, Burley tobacco growing 39 

yellow tobacco growing 41 

Texture, tobacco leaf, changes in curing 8, 13-15, 22-23 

relation to time of harvesting 10 

Tobacco, air-cming 12-22 

barn, heating system for flue-curing 42-44 

barns, construction 27-30, 41-44 

bright yellow, characteristics of color development 22, 24 

Burley, assorting 40 

color requirements 21 

cm-ing 40 

harvesting 40 

packing. .... 40 

sections where grown 39 

cigar, air-ciu-ing 12-21, 27-36 

color requirements 34 

curing 33-35 

barn, construction 27-30 

harvesting 30-33 

injury by humidity; 15, 34 

ripeness, relation to color.. . . . . 9-10 

stripping, assorting, and bulking 35-.36 

wrapper leaf, shade-grown, harvesting and curing 36-39 

color and texture, changes in curing. 8, 13-15, 22-23, 24 

Cuban and Sumatra, harvesting and curing 36-39 

shade-grown, harvesting and curing 36-39 

curing picked leaves compared to curing on stalk 10-12 

practical methods as applied to various types. 27-51 



54 PRINCIPLES AND METHODS OF CURING TOBACCO. 

Pago. 

Tobacco, curing principle!? 7-25 

with open firet; 20, 25 

export, curing - 47-50 

grading 49 

handling 49-50 

harvesting 48 

marketing 49 

packing 49 

prizing 49 

flue-curing 22-25 

leaf, changes in composition, etc. while curing 8-9, 13-15, 22-23 

Perique ' ' carottes, ' ' preparation 50 

growing, harvesting, curing, and rolling 50 

rolls, description 50 

ripening, color and texture changes 9-10 

shade-grown cigar-wrapper leaf, harvesting and curing 36-39 

"strawy " condition, causes 10, 13 

stringing 31, 37, 44, 48 

Sumatra, shade-grown, harvesting and curing 36-39 

sun-cured, production in \'irginia 21-22, 41 

types, color requirements 9-10, 21, 34 

vitality after cutting 11,13 

yellow, assorting 47 

Inilking and bleaching 46-47 

characteristics of color developmeul 22, 24 

curing 12. 22-25, 45-46 

barn, construction 41^ 

growing, soils suitable 41 

handling after curing 46^7 

harvesting 44-45 

Tobaccos, cigar, curing methods 12-21, 27-36 

high-priced, priming method ol curing 11 

Topping tobacco, effect on leaves 9 

Ventilation in curing tobacco, humidity, control 18-20, 23, 33, 34 

necessity 18-20, 23, 28, 33 

Ventilators, tobacco barn, directions for i)lacing 29, 30, 42 

Virginia, yellow tobacco growing 41 

Water, capacity of air at different temperatures 20 

removal from tobacco in curing 15 

Weather conditions, tobacco curing, need of control 16, 18, 33 

West Virginia, Burley tobacco growing 39 

Yellow coloring matter in tobacco, changes in curing 14, 22, 24 

143 

o 



b JL '09 



